Fixing up standard library symbols per requirements

http://www2.cs.uidaho.edu/~jeffery/courses/445/lecture.html#31
Making list ignore inserts of empty data
Basic class member definitions working
Adding compound statement rule so all functions have a statement subtree

Helped with empty and single statement functions
Refactoring handle_param_list()

- Only recurse on subtree if not a leaf
- DRYer handle_function()
Updating tests for member function definitions