Merging `release/4.6` to `develop`

Conflicts with:
* WordPress/Classes/ViewRelated/Notifications/Controllers/NotificationDetailsViewController.m
* WordPress/Classes/ViewRelated/Reader/CommentContentView.m
* WordPress/Classes/ViewRelated/Reader/ReaderCommentsViewController. m

Unresolved:
* WordPress/Classes/ViewRelated/Reader/ReaderCommentsViewController.m