I fixed that bug, but my item is still showing the missing texture. The log says "[19:22:38] [Client thread/ERROR]: Using missing texture, unable to load letsmodreboot:textures/items/mapleLeaf.png", but I think that's the correct path...
[spoiler=Full log]
[19:22:27] [main/INFO]: Setting user: ForgeDevName
[19:22:28] [Client thread/INFO]: LWJGL Version: 2.9.1
[19:22:35] [Client thread/INFO]: Reloading ResourceManager: Default, FMLFileResourcePack:Forge Mod Loader, FMLFileResourcePack:Minecraft Forge, FMLFileResourcePack:Lets Mod Reboot
[19:22:36] [sound Library Loader/INFO]: Sound engine started
[19:22:37] [Client thread/INFO]: Created: 512x256 textures/blocks-atlas
[19:22:38] [Client thread/ERROR]: Using missing texture, unable to load letsmodreboot:textures/items/mapleLeaf.png
java.io.FileNotFoundException: letsmodreboot:textures/items/mapleLeaf.png
at net.minecraft.client.resources.SimpleReloadableResourceManager.getResource(SimpleReloadableResourceManager.java:71) ~[simpleReloadableResourceManager.class:?]
at net.minecraft.client.renderer.texture.TextureMap.loadTextureAtlas(TextureMap.java:126) [TextureMap.class:?]
at net.minecraft.client.renderer.texture.TextureMap.loadTexture(TextureMap.java:91) [TextureMap.class:?]
at net.minecraft.client.renderer.texture.TextureManager.loadTexture(TextureManager.java:89) [TextureManager.class:?]
at net.minecraft.client.renderer.texture.TextureManager.loadTickableTexture(TextureManager.java:71) [TextureManager.class:?]
at net.minecraft.client.renderer.texture.TextureManager.loadTextureMap(TextureManager.java:58) [TextureManager.class:?]
at net.minecraft.client.Minecraft.startGame(Minecraft.java:593) [Minecraft.class:?]
at net.minecraft.client.Minecraft.run(Minecraft.java:941) [Minecraft.class:?]
at net.minecraft.client.main.Main.main(Main.java:164) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[?:1.7.0_67]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_67]
at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_67]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134) [launchwrapper-1.9.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.9.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[?:1.7.0_67]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_67]
at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_67]
at GradleStart.bounce(GradleStart.java:107) [start/:?]
at GradleStart.startClient(GradleStart.java:100) [start/:?]
at GradleStart.main(GradleStart.java:55) [start/:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[?:1.7.0_67]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_67]
at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_67]
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134) [idea_rt.jar:?]
[19:22:38] [Client thread/INFO]: Created: 256x256 textures/items-atlas
[19:22:38] [Client thread/INFO]: Reloading ResourceManager: Default, FMLFileResourcePack:Forge Mod Loader, FMLFileResourcePack:Minecraft Forge, FMLFileResourcePack:Lets Mod Reboot
[19:22:38] [Client thread/ERROR]: Using missing texture, unable to load letsmodreboot:textures/items/mapleLeaf.png
java.io.FileNotFoundException: letsmodreboot:textures/items/mapleLeaf.png
at net.minecraft.client.resources.SimpleReloadableResourceManager.getResource(SimpleReloadableResourceManager.java:71) ~[simpleReloadableResourceManager.class:?]
at net.minecraft.client.renderer.texture.TextureMap.loadTextureAtlas(TextureMap.java:126) [TextureMap.class:?]
at net.minecraft.client.renderer.texture.TextureMap.loadTexture(TextureMap.java:91) [TextureMap.class:?]
at net.minecraft.client.renderer.texture.TextureManager.loadTexture(TextureManager.java:89) [TextureManager.class:?]
at net.minecraft.client.renderer.texture.TextureManager.onResourceManagerReload(TextureManager.java:170) [TextureManager.class:?]
at net.minecraft.client.resources.SimpleReloadableResourceManager.notifyReloadListeners(SimpleReloadableResourceManager.java:134) [simpleReloadableResourceManager.class:?]
at net.minecraft.client.resources.SimpleReloadableResourceManager.reloadResources(SimpleReloadableResourceManager.java:118) [simpleReloadableResourceManager.class:?]
at net.minecraft.client.Minecraft.refreshResources(Minecraft.java:653) [Minecraft.class:?]
at cpw.mods.fml.client.FMLClientHandler.finishMinecraftLoading(FMLClientHandler.java:303) [FMLClientHandler.class:?]
at net.minecraft.client.Minecraft.startGame(Minecraft.java:596) [Minecraft.class:?]
at net.minecraft.client.Minecraft.run(Minecraft.java:941) [Minecraft.class:?]
at net.minecraft.client.main.Main.main(Main.java:164) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[?:1.7.0_67]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_67]
at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_67]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134) [launchwrapper-1.9.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.9.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[?:1.7.0_67]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_67]
at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_67]
at GradleStart.bounce(GradleStart.java:107) [start/:?]
at GradleStart.startClient(GradleStart.java:100) [start/:?]
at GradleStart.main(GradleStart.java:55) [start/:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[?:1.7.0_67]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_67]
at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_67]
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134) [idea_rt.jar:?]
[19:22:38] [Client thread/INFO]: Created: 256x256 textures/items-atlas
[19:22:38] [Client thread/INFO]: Created: 512x256 textures/blocks-atlas
[19:22:40] [sound Library Loader/INFO]: Sound engine started
[19:23:26] [Client thread/INFO]: Stopping!
I pushed the change(s) to Github again.
EDIT:
The name, creative tab and stacksize do work.