Added Bandit UCB1 implementation

********* PEOPLE *************
Primary reviewer: @sc932 

Reviewers: @suntzu86 

********* DESCRIPTION **************
Branch Name: norases_354_ucb1_bandit
Ticket(s)/Issue(s): #354 

********* TESTING DONE *************
make test
make style-test
i think this blob (picking the off the best payoffs where multiple equal winners are allowed) is duplicated btwn here and epsilon.py. another candidate for utils if they're actually the same?