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'd see what you are using the most (or look in the other rest tests) and pick one way to name test classes.