Fix a URL I missed in the Channel Editor. Also fix the broken link to the Channel Icon.
Enable forward-only cursors with all prepared database connections.

QT docs indicate that there are significant speed ups and a reduction
in memory usage by enabling forward-only cursors. Since mysql only
supports forward only cursors QT must cache the entire result set in
memory in order to support bi-directional iteration and seeking. By
explicitly telling QT that we only care about iterating forward
through the result set QT can avoid this caching.

Unconditionally enable this since all existing uses of the database
iterate forward over the result set.