Added windows support to file manager.

Added a windows clone of dirent.h and made some conditional changes to
the current working directory code.
Didn't capitalize cwd.
Removed dependency on 3rd-part dirent.h

Switched to an all WINAPI method for the windows version.
Fixed some capitalization.
Merge pull request #3 from Secronz/master

Github didn't notify me... Added windows support to file manager.