flexcdc: better parse $activeDB, move mvloglist check after schema determination

This fixes table references without schema in ALTER TABLE
flexcdc: be sure to call process_rowlog() just after mvlog creation (auto-changelog mode)
read raise_warnings from the correct part of the ini
Merge pull request #91 from disq/better_column_alters

flexcdc: better parse $activeDB, move mvloglist check after schema determination