refs #369, changed interpolation to a working (but still too bad performing) version

* using split by callsign everywhere
* helper function to insert_front
* revised linear interpolator
* renamed to remoteAircraft
* renamed to container() in providers (gettters are usually copies)

Issues why changes did so long:
* insert in list is not adding in front, but same as push_back (that was confusing)
* naming of values before/after in interpolator was ambigious
* QMap keeps values sorted by key, not arbitrarily

src/blackmisc/avcallsignobjectlist.h

@@ -71,10 +71,10 @@ namespace BlackMisc
             ICallsignObjectList();
 
             //! Container
-            virtual const CONTAINER &getContainer() const = 0;
+            virtual const CONTAINER &container() const = 0;
 
             //! Container
-            virtual CONTAINER &getContainer() = 0;
+            virtual CONTAINER &container() = 0;
         };
 
     } //namespace