Mark a pull request review as "complete" (separately from "approved")

Our pull request git work flow goes like this:

A developer performs work in a feature branch, and once complete, creates a pull request in order to get it merged into master. The rest of the team (~4 members) all take part in a code review. One member of the team (and not the author) is designated as the primary reviewer. This person's job is to ensure that the points raised in the review really do get fixed before the code is merged.

It would assist our workflow if Stash allowed reviewers to indicate that they had finished the code review, even if they haven't approved it. Really they're saying they've finished one pass through the code. They may be withholding their approval because of issues they've raised, but they won't be making any more comments until the fixes are committed.

This helps the author by letting him know that the reviewers have looked at the code and have finished with their appraisal - letting the author make changes knowing that no further comments are likely to come in offering a counter-opinion.

This helps the primary reviewer to know that his colleagues have completed the review, but are withholding their approval until some issues are fixed.