Add Windows OS support

[svoitovich]

Rsynk has some platform-dependent code such as retrieving file system information and reading all kinds of file information like owners, permissions, etc.

To add windows we should add another implementation of FileSystemInfo (apart from UnixDefaultFileSystemInfo) and load correct implementation on application start.

P.S. there are tests that uses FIleSystemInfo, to make them work on windows the different implementation should be provided there as well (search for issue#2 in code).