test(rxNotify): Add simple exists function for notifications
test(rxNotify): changes for protractor 1.3.1

Changed rxNotify page object to support protractor 1.3.1.
Ran into an issue with map causing protractor/selenium to crash unexpectedly.
Resolved via changing .map function to a .reduce.
Reported to upstream protractor project.
Merge pull request #603 from rackerlabs/rxNotify-exists

Rx notify exists