[2.0] DDC-91 - Enhanced SchemaManager::listTableIndexes() considerably. Add primary keys to the index list, add a bool flag primary to each index, add an array of columns to each index. Moved a test to SchemaFunctionalTestCase to check that every database (Mysql, Pgsql, Sqlite, Oracle) returns exactly the same data from this function.

[2.0] Fixes and enhancements to sequence generators. Test suite now runs & passes against postgres. Other minor, unrelated cleanups.