Global Git Ignore file for Unity projects

This can be used as a base as of Git Ignore file for Unity projects:

/[Ll]ibrary/
/[Tt]emp/
/[Oo]bj/
/[Bb]uild/

# Autogenerated VS/MD solution and project files
*.csproj
*.unityproj
*.sln
*.suo
*.tmp
*.user
*.userprefs
*.pidb
*.booproj

If you have lots of Unity projects, you can add/use it as Global Git Ignore file instead.