Modified version of the cc500 compiler from http://homepage.ntlworld.com/edmund.grimley-evans/cc500/
I've added the following features:
- Python-style whitespace syntax with colon and tabs
- Elimination of semicolons
- Addition of single hash as line comments
- Added the rest of the relational operators <=, >, >=
- multiplicative_expr including * / %
- improved error handling and messaging