URBNG-137 - [WP] implement sending answer to server

URBNG-153 - [WP] Use GameAuthorizationService in GameWebService (implemented CredentialsService)
URBNG-153 - [WP]Implement api communication for games (join/leave implemented)
URBNG-153 - [WP]Implement api communication for solutions (sending abcd and gps solutions - without receiving points and result)
URBNG-141 - [WP] "New task available" notification
URBNG-143 - [WP] Mark changed game as provided in UX spec
URBNG-143 - [WP] Mark changes in game as provided in UX spec
URBNG-153 - [WP] refactor WebService to final version

Also:
* fixed GameAuthorizationService
* fixed GamesListView
* removed unnecessary columns in Game
* added CharId in IABCDPossibleAnswer
* blocked sending ABCD solutions without selected answer(s)
* fixed data in GameWebServiceMock
* auto generating id in ABCDPossibleAnswer
* fixed game icons in mock
* fixed data comparing in GameChangesManager
* fixed TaskViewModel
* fixed TaskView
* fixed submitting abcd solution
* blocked sending solutions from abandoned games
* fixed GameChangesManager