Changed eval_file to read_file

Will now not automatically run execute file and free the data anymore.
This is so we can reuse it for compilation later.
Renamed brainfuck and functions to brainfuck_repl

This is so we can separate them easier from compiler later
Add brainfuck_main.h

Also split main function into two
Made skeleton for NASM-mode
Can now parse BF to NASM

Sadly, it's not 100% bugfree yet. HELLO_ISSUE1 does not work