Added Bandit epsilon-greedy implementation

********* PEOPLE *************
Primary reviewer: @sc932

Reviewers: @suntzu86

********* DESCRIPTION **************
Branch Name: norases_255_create_epsilon_greedy_bandits
Ticket(s)/Issue(s): Closes #255 

********* TESTING DONE *************
make test-no-tox
make style-test-no-tox
not a big deal, but i dont see why you need to sort here. you just need the max value; nothign else depends on sorting. (and in fact if you do sort, you can simplify the zip and filter steps b/c only the first M entries can have payoff == best_payoff. so find the first index and grab winning_list = avg_list[:M])