Added settings window that allows switching to the MJ 1 GUI skin.
Fix signs for an angle's text representation.
Added a "restore factory defaults" to the settings window.
Autostaging options now minimize when autostaging is off.
Thrust limiter toggles now light up green when active.
Fixed #80 (ILS navball guidance was only working when autopilot was on).
Actually adding MechJebModuleSettings.cs.

I had forgotten to actually commit it before!
Merge remote-tracking branch 'upstream/dev' into dev