bulkdelete: add basic integration test

This adds a basic integration test for bulk-deletion of docs

COUCHDB-2462
Fix ACE document editor cutting off long lines of code

Closes COUCHDB-2454
Enable passing a single test to nightwatch

You can now pass single testfiles to nightwatch which makes
development of tests easier and faster.

Example:
`grunt nightwatch --file="createsDatabase"` launches the
createsDatabase.js testfile in app/databases/tests/nightwatch

Happy testing!