Add expression parser module.
Add basic expression parser infrastructure (all tests pass).
Support defined operator.
Support ==, !=, and !.
Support parenthesized conditional expressions.
Improve run-test output on exceptions.
Add expression parser for +,-,* and / operations.
Test suites 1-8 succeed with new expression parser.
Expression parser passes test suite 9.
Support C/C++-style blocks.
Add GitHub markdown README.