* added unload function to disconnect signals / slots and simulator
* changed remote provider to return signal/slot connections to manually disconnect functor connects
* flag so pause can freeze or continue AI aircraft
* slightly changed unload behaviour in simulator context
Remark: Tested for FSX only
Solves #424 for FSX
* added snapshot class
* added snapshot in analyzer, signal for new snapshot
* made all provider signals available in CSimulator
* added finders in CSimulatedAircraftList
* moved COwnAircraftProviderDummy into own file
* access via provider, access now possible also beyond the scope of interpolator
* will be used in (to be written airpace analyzer)
* renamed some member functions as required
* fixed some asserts / Doxygen comments
* adjusted unit tests
* added vtolAircraft flag for interpolator, not fully used everywhere
remarks: update signals for parts / situation still only needed in XP driver