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
is there any significance to these values? (well clearly 2 are edge cases)

are there value(s) that you would "suggest" for standard use? (if so, i'd add a test value in that range too)