Instead of enabling fast position updates via context methods, the
settings API will be used instead. This also allowed to move the timer
into CNetworkVatlib instead of CAirspaceMonitor. The only necessary thing
was to regularly update the receiver callsign set.
refs #677
The following issues were fixed
* Fixed wrong/missing namespaces
* Fixed obvious typos in documentation
* Documentation not in sync with source code
refs #544
* preparation for a context menu to send text messages from ATC/aircraft view
* preparation for context menu for fast pos. updates
* reverse ICAO lookup at login screen
* display fast updates / parts in GUI
* moved max- aircraft into settings
* made serverselection own component