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/timestampbased.cpp

@@ -64,7 +64,7 @@ namespace BlackMisc
         return otherTimestampObj.m_timestampMSecsSinceEpoch - this->m_timestampMSecsSinceEpoch;
     }
 
-    qint64 ITimestampBased::msecsToAbs(const ITimestampBased &otherTimestampObj) const
+    qint64 ITimestampBased::absMsecsTo(const ITimestampBased &otherTimestampObj) const
     {
         qint64 dt = this->msecsTo(otherTimestampObj);
         return dt > 0 ? dt : dt * -1;