(Issue 3386) Add alert-warning for etherpad content alerts
Make etherpad warning style consistent with unembeddable link warning
Merge remote-tracking branch 'bert/bootstrap3' into issue-3386
Align etherpad warning text in the center
Merge branch 'issue-3386' of https://github.com/bp323/3akai-ux into issue-3386
Remove custom styling for empty document message