Expanded tests for kmeans package

This contains a lot of new tests to maximize the coverage of the kmeans package. There is only 1 missing branch uncovered(https://github.com/cbmi/avocado/commit/4e82bfb17e9fb664a01fd8e734322edfc70e448f). Additionally, there are a number of bug fixes included for the kmeans package that were discovered during the expanded testing. Finally, https://github.com/cbmi/avocado/commit/bfd25d6bdca2b44f16f697737dc91fad949d7d02 fixes https://github.com/cbmi/avocado/issues/102.