Removing test from all make target

Per Dr. J
Trying to generate intermediate code from main
Returning null from get_node() if child tree not found
Adding TESTFLAGS to Makefile
Passing yyprogram from main
Fixing up some opcodes and shortening empty address name to e
Handling function scopes

Still need to handle class scopes and fix buggy lookup of constants.
Handling leaf nodes in code_generate()

Their the base case for the recursion, doing nothing but checking
themselves for debugging purposes.
Fixing default concatenation of children code

Was accidentally trying to compare the tree as a node, need to unwrap it
first. Ugh void pointers.
Adding a bunch more cases for intermediate code generation

Attempting to handle a simple test case "Fibonacci"
Adding task for libraries

`list_concat()` spouts an error when passed two NULL lists, which in
some cases is a desired use. Should make debug messages optional.