Merge pull request #1 from ksundberg/master

Update from class
This implements a function that creates a map that maps basic blocks to their parents. It is useful for data flow analysis.
Merge pull request #2 from ksundberg/master

Pull from ksundberg
Make memory offsets for non global variables negative. Moved FlowGraph class. Added a < function for ThreeAddressInstruction
Actually fixed variable access in functions this time. We were always using the current scope to determine if a variable was in global memory or on the stack. Now symbols know if they are global or local so we can get the correct base pointer and offset.
Moved the memory offset to the scope so the it gets reset when we leave a scope. We were just incrementing it for every variable in the program.
Merge pull request #29 from zepedebo/master

Pull from master