added easy literal cases to SA
planning assignment. done for the night
implemented binop for atom types
expr handles basic id recognition
handles basic assignment
fixed assignment s.t. only id is allowed on the lhs
seems like we are able to check tree TYPES, have not yet implemented degree checking
CHECKING DEGREES NOW QUESTION MARK EXCLAMATION MARK
got rid of separate function to check degree of tree (unecessary)
commit pre-merge to master
Merge pull request #7 from dmb2168/chris_kira_semantic_analysis

Chris Kira Semantic Analysis