in-progress work on modals
updating to follow latest liquid-fire release
Merge branch 'master' into modal
visibility control for modal popup transition
vertical centering modals: stick with happy standard flexbox for now
Merge branch 'master' into modal

Conflicts:
	app/router.js
make modal animation run even at initial insertion
modal controller mixin
working modal controller mixin
lots of progress on modals
modal dismiss protocol
tab trapping
more tab focus control
adding accessibility attrs
don't append modal container until needed
documented modals
minor style precedence
starting to add a test
Merge branch 'master' into modal
starting to extend router dsl