Implement support for --chmod and --chown rsync flags (supersedes PR #46)

Created by: dkasak

I've implemented most of the things you asked for, except testing the new features. I'm not sure how to approach testing the --chown functionality since I don't know which users/groups I can rely on being present in the testing environment.

Regarding --chmod, I have started implementing tests but I'm not sure what's the best way to organize them. I've thought about making a new test_chmod sync dir with a single file inside it with certain permissions set up, then adding a new test case test_afl_rsync_chmod which tests push/sync by using --chmod to change permissions and verifying they are correct (by calling AflRsync directly). How does that sound?

I'm in a bit of a hurry, so sorry if something's unclear.