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
i see that epsilon is a particular hyperparameter.  whether this method should take ```hyperparameter_info``` as a dict and read epsilon out of it OR your current implementation is up to you.

passing ```hyperparameter_info``` around is more generic. (i generally prefer this)
passing ```epsilon``` is maybe a little more clear for this one method (BUT it may force you to have specialized code upstream to construct each bandit strategy separately)