Added correct termination of program by KeyboardInterrupt
Add exception NotTaskException, which raised when task is not applicable
for task manager. Extended method new_task - functions can ba added by
self.
changing kwargs parameter in tasks
Enabled entity manager
Adding new handles of exceptions, changing checking of connection
existence, fixed bugs
Added commandHandler, which can get commands from server and handle them
Commented some logger records
Tasks for task manager. Added first task get_commands