- Impl. unary bool not "!"
- Impl. relational exprs (">", ">=", "<", "<=")
- Impl. equality exprs ("==", "!=")
- Impl. bool and, or, xor ("&&", "||", "^^")
- Changed bool xor lexing from "^" to "^^" in order to keep "^"
reserved for bitwise xor
- Prepared Ast for if, while & fn_def statements