Updated win_file so it is at parity with the *nix version where possible.

There could be some breaking changes in here, including:
* the broken sed, sed_contains, patch, uncomment, comment functions were removed (sed and patch executables don't exist on Windows by default)
* follow_symlinks functionality was added where applicable and made to comply with *nix behaviour
* return values were changed to match *nix behaviour
* the stats function now includes user and group details
* get_group and get_gid now actually return the group, not the user as it previously did
Added file.lchown so Salt can use a different implementation for Windows.