add unit busted tests

Since we are under going a big rewrite of the code base right now, a legit test framework is going to help a lot. So I picked busted project: http://olivinelabs.com/busted/

It's really easy to run the test. Just install luajit, luarocks. Then use luarocks to install busted package. Last, run busted command in kroeader-base's root directory.

I have converted tests from #89 to busted tests.