Use rake jasmine:ci now that jasmine can do phantom running by itself

Required "upgrading" to gmaps4rails 2.x, since gmaps4rails 1.x
inadvertently loaded its own copy of jasmine.rake on boot, which
caused rake jasmine:ci to explode. gmaps4rails 2.x is all different
though, so there might be some cool regressions.

Remove code that installed phantomjs on TravisCI, because Travis
now has a newer version of phantom than the one we're trying to
install. time has continued to march on!!