Merge pull request #1481 from Tandoori/fix-unity-root-folders

Made it so the folders only get ingored in the root

Unity.gitignore

-[Ll]ibrary/
-[Tt]emp/
-[Oo]bj/
-[Bb]uild/
+/[Ll]ibrary/
+/[Tt]emp/
+/[Oo]bj/
+/[Bb]uild/
 
 # Autogenerated VS/MD solution and project files
 *.csproj