Implement Epsilon-First bandit endpoint

********* PEOPLE *************
Primary reviewer: @sc932

Reviewers: @suntzu86

********* DESCRIPTION **************
Branch Name: norases_335_create_epsilon_first_bandit_endpoint
Ticket(s)/Issue(s): Closes #335

********* TESTING DONE *************
make test
make style-test
i'd add a test that does ```T.assert_raises``` to verify that a ValueError is raised when the list is empty.
You may need to disable logging if this produces extra prints.

See moe.tests.views.exceptions_test.py for examples of disabling logging & using assert_raises