Reviews can now be published to the review request submitter only. When

published this way, only the submitter and reviewer will receive

e-mails about the review (if they both have e-mail acitivity enabled).

All other users in the target review groups or reviewers will not

receieve e-mails about the review. This is particularly useful when the

review consists of pointing out a small typo, etc.
As such, the review_published signal now expect another argument,

to_submitter_only, which indicates if the review is only for the

review request submitter.
Unit tests have been added to test the front end and backend behaviour.
The new RB.SplitButtonView has been added to facilitate the UI

changes for this patch. It consists of a primary button and a drop down

control which, when hovered, will display a list of alternative

actions.

Ran unit test.

Ran JS tests.
Published a review to a review request that was assigned to more than

one reviewer. Only the review request submitter and review publisher

received e-mails.