[server] stop blocking cross-origin iframes
Merge branch 'master' into allow_cross_origin_iframe

Conflicts:
	src/server/lib/app.rb

	renamed:    src/kibana/apps/discover/controllers/discover.js -> src/kibana/plugins/discover/controllers/discover.js
Merge pull request #1717 from spenceralger/allow_cross_origin_iframe

[server] stop blocking cross-origin iframes