Disable saving of effect chains since loading is disabled.

Prevents committing to an XML format before we are ready.
Delete unused ControlObjectSlave in EffectSlot.
Re-add EffectSlot::debugString() and update EffectChainSlot::debugString().
Typo fix in method name and check for NULL controls since Samplers and
PreviewDecks do not get EQ effects.
Aliases should live near the code that they alias to.
Remove double-hash lookup in ControlDoublePrivate::getControl.