* return interpolation results parts/situation in one step
* base class init for each interpolation step, less redundant code
* removed old interpolation/parts function
* adjusted unit tests and simulator objects (such as SimObject)
* using interface IInterpolant, renamed to CInterpolant for concrete implmentation
* CInterpolatorPBH has itws own file now, is included
* linear interpolator only re-calculates interpolant when needed (same as spline interpolator)
* use CAircraftSituationChange
* recalculate interpolant if situation changed (due to elevation update)
* keep extra info string for debugging
* improved situation checking
* split functions, added findClosestElevationWithinRangeOrRequest
* obtain elevation ids (separate ids are easier to track)
* also added experimental "physicallyAddAITerrainProbe" (FSX) for the FSX elevation probing
* callback / signal when requested elevation is received (async)
* interpolators use providers for client/situations/parts/ground elevation
* interpolators do no longer use own situations/parts, but those from provider
* interpolators are no longer QObjects (as it is not needed)
* use gnd flag from situation for gnd interpolation, there is no longer a parts gnd flag interpolation
* guess parts during interpolation
* changed iterators to m_s[i] as it makes clearer which values are used
** the flag is transferred from parts -> situation in airspace monitor
** if the other client already provides and gnd.flag in situation this also works
* adjusted logging
* use providers in unit tests / adjusted tests
* improved situation verification/assert
* As there are no longer situations/parts added to the interpolator /solely provided by provider) there is no overhead anymore and no need for the dummy interpolator.
* Furthermore switching the interpolator at runtime will become possible.
* this implementation is used by airspace monitor
* also used by dummy provider (advantage, unit tests test the real provider)
* some functions adjusted
* no longer using the add parts/situations signals
* will use the remote aircraft provider parts directly
Result: all parts/situations are stored only once in memory and in one single place
