first implementation of Database_SQLite (does not pass all tests yet)
fix in Config_Db - file has not to be present (makes sense only for SQLite)
database fixture - data filling simplified (constraints and foreign keys specified in CREATE TABLE)
database fixture - data filling simplified
SQLite - added column list to insert statements generated by exportData; SQLite now passes all tests
cyclic references: test, fix in PostgreSQL clearing, deleteTable in databases replaced by clear (which was in DatabaseUtils), deleteTable_internal in databases does not force deleting by disabling constraints
cyclic references: test, fix in PostgreSQL clearing, deleteTable in databases replaced by clear (which was in DatabaseUtils), deleteTable_internal in databases does not force deleting by disabling constraints