Added option 'exposeAddClass'

Adding option 'exposeAddClass' adds extra class to exposed element. This fixes a problem with exposing elements with no background(-color).
Handle elements with no classes correctly
update readme to include Reactor
Merge pull request #2334 from awshout/update-readme

update readme to include Reactor
Merge pull request #2292 from niklam/patch-1

New setting 'exposedAddClass' to joyride
Disable mousedown on custom select.
Merge branch 'master' of github.com:zurb/foundation
Allow disabling of scrolltop for stick nav.
update documentation to not mention normalize
Fixed Clearing featured image on mobile
Added .clearing-featured-img class to designate the featured image in a .clearing-feature list
Merge remote-tracking branch 'upstream/master'

Conflicts:
	js/foundation/foundation.forms.js