SYIOS-26 Make the app usable when starting the app offline.
Store user displayname & avatarUrl in MXStore.
Let MXUser use the MXStore to store user displayname & avatar
SYIOS-26 Make the app usable when starting the app offline.
Added another callback parameter to [MXSession start]: onStoreDataReady to indicate when the app can start to work offline
SYIOS-26 Make the app usable when starting the app offline.
Implemeter MXSession start onStoreDataReady callback. The test is not working yet