The trackinfo is now persisted after the preprocessing of a given track is done, and not every time a db_handler is closed. As a consequence of this change, one of the tests failed due to a ramaining open filehandler of a db file that had been renamed in the table merger. Possible remaining open handlers are now closed after their associated db filename is changed (haven't figured out why this happens yet)
Temporary gtrackcore_dir hack until GTRACKCORE_DIR env is set on insilico