Fixed #179

Turns out you need to use a promise to ensure that the notification for status is sent *before* the ticket has been closed (if stay on ticket is not selected)
added a promise that should still succeed even if the network request fails, if network request fails the notification will not be sent.
Changed POST to PUT for tags.json

OH GOD OH GOD NOT THE BEEES
not sure how this one got past QA - critical fix
fixes #181
Added ability to remove tag from open tickets

- adds flexibility
- satisfies feature for #183
- some modifications to nofication strings to make things consistent with new behavior.
Minor fix to notification wording
Merge pull request #182 from zendesklabs/b/181

Changed POST to PUT for tags.json
Merge pull request #180 from zendesklabs/b/179

Fixed #179
Merge pull request #184 from zendesklabs/b/tag_enhancement

B/tag enhancement
Merge branch 'stable/2.5'

Conflicts:
	lib/update_status.js