Added the MessageRequestsViewController
Added a 'Message Requests' button to the settings screen
Added accept/reject buttons for message requests to the ConversationVC
Added the ability to hide the message request item on the HomeVC (re-appears if you get a new message request)
Added code to handle an edge-case where the message request approval state wouldn't be returned to the sender due to the recipient running an old version of the app
Prevented contacts which aren't associated with an approved thread from appearing when creating a closed group
Disabled notifications for threads which aren't approved
Updated the app notification count to exclude unapproved messages
Updated the app to ignore closed group creation messages if the group has no admins which are approved contacts
Fixed up the keyboard avoidance behaviour in the ConversationVC
Fixed a couple of minor interaction issues which affected some devices
Fixed an issue where the database migrations would run on the 2nd launch when creating a new account (causing odd behaviours)
