TRACK_SNAPSHOTS has SNAPSHOT_ID to distinguish snapshots better than with 1s resolution.
Added initialization of predictedLon/Lat/Mos in Track in constructor's initialization list.

It got rid with a problem when someone tried to access predictedMos,
which was not initialized properly (because estimation filter is working
in 2D space).
DynDBDriver::insertTrack() was replaced by TracksSnapshot class.

Added TracksSnapshot::Transactor (functor to perform transactions in pqxx's transactors framework).
DataManager puts track snapshots into DB.