Filter and reject "--config" and "--debugger" flags to Mercurial in any position
Additionally, harden some Mercurial commands where possible (by using additional quoting or embedding arguments in other constructs) so they resist these flags and behave properly when passed arguments with these values.
- Added unit tests.
- Verified "--config" and "--debugger" commands are rejected.
- Verified more commands now work properly even with branches and files named --debugger, although not all of them do.
Reviewed By: amckinley
Maniphest Tasks: T13012
Differential Revision: https://secure.phabricator.com/D18769