Add Executioner::terminate() (#3735)
Add Terminator UserObject (#3735)
Deduce needed postprocessors (#3735)
move logic from Executioner into Problem (#3735)
Move Terminator UO into core, new test (#3735)
fix missing initializer (#3735)
Simplify test, fix "teh" (#3735)
make test non-random (#3735)
Merge pull request #3739 from dschwen/terminate_3735

Terminate solves cleanly based on Postprocessor values