Merge in latest changes from Group 17 repo.

Few changes here,

1. Delete unnecessary files.
2. Added INDENT / DEDENT support in Hakaru.g4.
3. Added HakaruToTensorFlow.java (main translator program).
4. Added HakaruToTensorFlowListener.java (Listener subclass of HakaruBaseListener). This is where the code generation functions are overridden (e.g. enterFuncdef).

merged

mentioned in commit 87e1c305