Start building Monte-in-Monte language tests.

It doesn't quite work yet, though.
runtime: Add negation of ints and test.
src/test: Test properties of bools.
Start testing lists.
Start building derp-style parser.
Add isInteger primitive and show off the int guard in Monte.

This is pretty cool!
Demonstration code for intervals.
runtime: Enable addition on ConstLists.

More or less.
More work on derp.
runtime: Start building a MonteChar type.
More derp.