update notif msg. to be consistent with the ups-guide
Link to REST API and Node.js Sender example
fix language issues (fail back / to be send)

Conflicts:
	docs/unifiedpush/aerogear-push-ios/unified-push-server.asciidoc
update SimplePush guide
fixed path to PushMessage.png image
Merge branch 'cvasilak_lfryc_fixes'