Update karma_calculator_spec file

My story: https://www.pivotaltracker.com/story/show/82978024
I wrote an it block to make every statement executed al least once. Thus increase coverage of the test. Only the changes to karma_calculator_spec relates to the chores. Other changes I made is my setup attempts and coverage testing on my machines.
Thank you. I will add more test that covers profile_completeness, membership_length and activity.