Checkpointing work.  Refs #6851.

Modifications include
1. Set PreserveEvents' default to True;
2. set StripVanadiumPeaks's default to True;
3. Set RemovePromptPulseWidth's default to 50;
4. Remove all "override" buttons in run setup tab related to
corrections (not fully tested).
Fix the enable/disable issue with van peak strip.  Refs #6851.
Merge remote branch 'origin/feature/6851_update_gui'