Make AutoApproverSpec work, fix AutoApprover bug.
Add RejectEdits, fix test cases

Also convert PagePartsTest from Specs2 to ScalaTest: there was some bug
that prevented me from setting breakpoints when using Specs2.
Make AutoApprover stop preliminarily approving comments

By using e.g. Post not PostAction in debiki-dao-rdb. Also fix some
EditActivitySpec things.
Break out class TestModeration

And in EditActivitySpec use clickGoBackToSite() not goBack().
Fix manual approval identification

Consider Approval.AuthoritativeUser manual if it's by another user than
the post author.
Replace Approval.Manual with AuthoritativeUser.
Make ModerationSpec work again, with properly prel approved comments.
Add 'Reject edits' button on moderation page, save RejectEdits in database

And have `Post.numEditsToReview` take rejections into account.
And rename hideRejectAndDeleteBtns to hideDeleteBtn.
Don't show unapproved edits.
Include ModerationSpec and EditActivitySpec in EndToEndSuite.
Merge branch 'topic-reject-edits'.