Kahlan integration.

[jmalloc]

@ezzatron has been promoting Kahlan as an alternative to Peridot due to it's wider adoption and likelyhood that it's capable of being extended to run tests as coroutines in much the same way as Peridot.

This doesn't necessitate porting the recoil/dev's own test suite to Kahlan, but that might also be desirable.

[ezzatron]

In terms of porting this project's test suite, it'll most likely be expect() that causes the most pain, but should be simple enough with a bit of regex search/replace. The biggest one is:

expect($actual)->to->equal($expected);

which becomes

expect($actual)->toBe($expected);