minor updates to wff and qf grammar
Updated grammar files, added QfWffChecker based on WffChecker
Renamed grammar files
Refactored WffChecker to be a superclass to Qf/TfWffChecker
Merge branch 'master' of ssh://github.com/PeterDrake/Logic

* 'master' of ssh://github.com/PeterDrake/Logic:
  Added negation method to formula evaluation and made a test for it
  Edited .gitignore and deleted Wff.g4
  evaluateFormula uses recursion to handle formula with multiple operators
  altered hilit functionality
  getTopLevelOperators can handle multicharacter operators
  Refactoring. Changed methods for evaluating a formula.
  Changed how operator functions work. Wrote formula evaluation for formulas with one operator. Tests included.
  Merged from master
  added conditional and biconditional
  added tables of correct values conjunction and disjunction
  added TruthTableChecker.java class

Conflicts:
	src/edu/lclark/logic/Wff.g4
Merged master into refactored wffchecker
Merge branch 'master' of ssh://github.com/PeterDrake/Logic

* 'master' of ssh://github.com/PeterDrake/Logic:
  more hilit
Merge branch 'wffchecker-future'

* wffchecker-future:
  Refactored WffChecker to be a superclass to Qf/TfWffChecker
  Renamed grammar files
  Updated grammar files, added QfWffChecker based on WffChecker