Config - add setup checks for minimum and "bad" versions of VCS software.

Summary: Fixes T3046. Git has no minimum or bad versions; svn has no minimum and the bad version of 1.7.1, and mercurial has a minimum of 1.9 and bad versions 2.2 and 2.1. These error messages are specific about the problem but do not include the details as to what specifically is bad about a given version. I don't think that's really necessary - the details don't help solve the problem and its probably booooooring at best to the average user. The details about a bad version are included in the code however.

Test Plan: hardcoded a VCS array to let me test all the VCS stuff. added some phlog() calls to make sure the VCS version parsing stuff was working correctly relative to the version(s) on my system. played around with setting minimum versions and bad versions and saw good results depending on what I set.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T3046

Differential Revision: https://secure.phabricator.com/D10852