Improve Testing Interfaces

[jaidetree]

Following up to #106:

• Replace describe with a macro similar to Clojure's testing macro
• Replace it with a macro similar to Clojure's deftest macro
• Replace is assertions with Clojure's is macro

Switching to macros here will cleanup the test code and in the case of Clojure's is, macro it has the ability to print both the expected\actual mismatch plus the test code itself in results.

[jaidetree]

One expected caveat is that every testfile may have to import the testing macros vs. global functions, but that also means alternative testing libraries are possible.