Added liked? and disliked? aliases to voter.
Updated docs according to the new aliases.
added cached_votes_score, which calculates upvotes - downvotes, for the ability to sort by good votes.
Merge pull request #24 from elado/master

Added cached_votes_score
Merge pull request #18 from Jeewes/patch-2

New PR which adds new aliases.
Merge pull request #25 from leizzer/master

Adding Scopes to votes
version bump
travis config
travis image in readme