Remove reference parser.
Move ast-* to ast/*.
Rewrite lexer.
Add support for bitwise operators, identifiers beginning with underscore, and octal integers to lexer and parser.
Implement backend for bitwise operators and add tests. Fix test-codegen issue with tmp.asm not getting deleted, resulting in failed tests.
Fix race in test-codegen.py by waiting for compilation process to finish before proceeding.
Update readme.
Rename scanner to lexer.