fix 1372 due to git HEAD file corrupted issue
Add .editorconfig file
Add reference to LibGit2Sharp
Remove useless xml doc
Make GitExeRepository.Resolve() private
Make GitExeRepository.CurrentId delegate to LibGit2Sharp
ToDos
Make build.cmd independent of current working directory
Make build.[cmd|proj] cope with VS2013 msbuild path changes
Make GitExeRepository.Exists delegate to LibGit2Sharp
Make GitExeRepository.Initialize() delegate to LibGit2Sharp