CTelegramDispatcher: Changed authenticated() signal emission conditions.

Consider that we are "authenticated" only if dc configuration is known.
CTelegramCore: Changed visible attributes for methods.

Now there is a lot of slots and invokable methods.
Dispatcher: Contact typing state now setted to false on message receiving.
CTelegramDispatcher: Unexpected typing status sending is mostly fixed.
testApp: Message text changed to empty now considered as stop composing.
testApp: Double click on contacts list now invoke messaging with contact.