* Add `stop` method to `Coordinator`
* Use new stop method to cleanup room screen
* Call stop implicitly when removing a child coordinator
* Revert placeholder avatar font change
* Fix PR remarks
Various logging fixes:
* imported the ObjCWrapper and updated the MXLogger. Also added back support for app containers
* updated MXLog.swift from El and fixed/improved its logging format
* updated most app log strings
* Remove unnecessary swiftlint rule
* Various tweaks following code review
* Added back type annoation on MXLogger logFiles method
* Fix generated Swift-ObjC header name
* #35 Create `ElementNavigationController` subclass
* #35 Add encryption icons
* #35 Add avatar and encryption badge image to the room screen view model
* #35 Create `RoomHeaderView` class
* #35 Replace room title with a RoomHeaderView instance in the toolbar
* #35 Add changelog
* #35 Introduce `UITestScreenIdentifier` and refactor ui tests
* #35 Fix old tests
* #35 add some tests for room screen
* #35 Use svgs instead of pngs
* #35 Fix PR remarks
- updated the authentication coordinator to use async await
- replaced the UserSession with a ClientProxy (similar to the RoomProxy)
- renamed `completion` to `callback` on the coordinators and view models
- renamed `viewModelResult` to `viewModelAction`
- introduced back UserSession as a user specific service container
