0.1

This is the first preview release of Urn, with a bare minimum of features implemented. In this release:

• Powerful macro system, allowing for arbitrary code execution and generation at runtime.
• Useful macro sets, providing features such as method call chaining, "power asserts" and a tiny testing framework.
• Useful error messages and diagnostics, ensuring your parentheses are always in the right place.
• A primitive optimiser, including constant folding and dead code elimination.
• Documentation generator.