Rewrited usage of QSqlRecord.

Avoided multiple creation of QSqlRecord (on calls query-
Corrected according to RRyan's recomendations.
Added member variable m_trackLocationIdColumn to TrackDAO.
Merge pull request #48 from troyane/CleanupQSqlRecord

Fix use of QSqlQuery::record() to reduce excessive copying of result rows. Fixes Bug #1201991.
A few more QSqlRecord changes.
Use CSAMPLE instead of float.