Will be useful when types are properly implemented

Currently we generate assembly that can be compiled using nasm.

Implemented language features so far:
- Pre increment/decrement operators
- Address-of and dereference operators
- Binary not operator
- Addition, subtraction operators
- Less-than operator
- Assignment operator
- Integer, character, and string literals
- Calling a few C library functions
- Integer variable, and pointer declarations
- While loop, if statement

It is still far from perfect. The .y file has been written based on
Annex A of the standard, so it should contain most syntactical elements.
Currently we only construct the AST from a single compound statement.
We have also implemented a debug print function for the AST, that should
output (mostly) valid C code.