* Show a yellowish note icon background for unapproved comments
* Removed `const` from the note keys to fix a build warning.
* Chaned `refreshBackgrounds()` to be run from each `layoutSubviews()` call.
Ensure we have a valid group before checking the comment status.
Removed an extra space.
Merge remote-tracking branch 'origin/develop' into issue/2536-notification-comment-icon-color

Conflicts:
	WordPress/Classes/ViewRelated/Notifications/Views/NoteTableViewCell.swift
NoteTableViewCell: Brings back setSelected and setHighlighted
Implements didChangeOverrides hack-helper
Merge pull request #2561 from wordpress-mobile/issue/2536-notification-comment-icon-color

Show a yellowish note icon background for unapproved comments