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
fixed. Master shows the following now:

* :mod:`moe.tests.bandit.bandit_test_case`: base test case for bandit tests with a simple integration test case
* :mod:`moe.tests.bandit.epsilon_greedy_test`: tests for :mod:`moe.bandit.epsilon_greedy.EpsilonGreedy`
* :mod:`moe.tests.bandit.epsilon_test_case`: test cases for classes under :mod:`moe.bandit.epsilon.Epsilon`
* :mod:`moe.tests.bandit.linkers_test`: tests for :mod:`moe.bandit.linkers`