Added "scrollThen" that can apply a scroll animation before another transition

Related to issue #76

Usage:

  this.transition(
    this.fromRoute('posts'),
    this.toRoute('post'),
    this.use('scrollThen', 'toLeft'),
    this.reverse('scrollThen', 'toRight', {duration: 100})
  );
prefer an injection rule
bugfix: bind correctly to modal aria options
adding dialogClass option for modals
minor improvements to modal-popup transition
releasing
updating for newer addon format
vendoring sinon because there's no usable up-to-date bower package
re-adding package metadata
drop duplicate metadata
prevent ember assertion
fix links from test page
dropping this so we're compatible with ember-cli 1.2
changelog
point at channel
select ember version in CI
rsvp compatibility
updates to match new source structure
going back simpler default bower
updating CI to build properly against all channels again