Add a getSymbol to Scope.java
Work on semantic rules for every loops
Merge branch 'master' of https://github.com/mymichellle/TT

This merge uses STRING instead of STRING_CONSTANT and timeFrameConstant instead of TIME_FRAME_CONSTANT

STRING_CONSTANT and TIME_FRAME_CONSTANT break the of the grammer.

Conflicts:
	TTInterpreter/src/columbia/plt/tt/TTGrammar.g