v0.0.1

Initial release. There is a lot of churn here, and signficant features include

• Simplification of simple arithmetic expressions (+, -, *, /, ^, %)
• Support for string-based pattern-matching rules
• Polynomial division in space Z
• Multiple output forms (pretty, s-expression, debug)
• Pretty-printed scanning and parser errors
• Support for implicit expressions, like multiplication (2x -> 2 * x)
• Integration test framework
• The ladder development tool
• The slide-bot triage and chore bot