Added documentation
Renamed QCL_APPLICATION_STATE to QCL_APPLICATION_MODE to avoid confusion over the term "state"
Added UI for displaying application mode
Polling frequency can now be configured using the QCL_EVENT_MESSAGE_POLLING_INTERVAL and QCL_EVENT_MESSAGE_POLLING_DELAYPERSESSION constants.
Doc fix
Updated todo.md
Removed on-the-fly creation of child and sibling sessions. Now, token must be explicitly created. Token lifetime handling not yet implemented.