Add some documentation for issue #212
Merge pull request #222 from adammulligan/master

Documentation for trial event hooks called from views
Add revis on travis
Merge pull request #226 from nberger/add-redis-on-travis

Add redis on travis
Split#initialize: Extract DEFAULT_OPTIONS
Extract extract_alternatives_from_options
Refactor initialize method

Makes more clear the difference between initializing from the
configuration when no alternatives are provided, from initializing
from the options
Experiment#initialize: Extract set_alternatives_and_options