Change color conversion API to support converting multiple colors in one request.
Switch to using HTTP POST for public conversion calls to support more clients and because we are posting data to be converted.
Move conversion tests into test/convert/* to follow API path spec; update Cakefile to pick up tests in subdirectories and only use javascript for the tests.
Fix mocha to actually search subdirectories when running tests. Whoops.
Add recipe calculation call, minor refactoring and add new unit tests for recipe calculation and common utility code.