Warn when leaving page with unsaved comment
Fix ARRAY(0x..) keywords when cloning bugs
Put cloned bug title into bug from which it was cloned
SQLite support, including EXPLAIN and FTS4 fulltext search
Make contrib/bzdbcopy.pl actually work with anything other than Pg,
independent of current localconfig.

Never use Bugzilla->dbh in Bugzilla::DB::Schema, store and use $self->{dbh} instead.
Replace LEFT JOIN with INNER JOIN whenever it's possible

This only has profit for SQLite; no profit for normal databases.