when dsp is destroyed, properly unhook itself from global space  even if there is no probe. also, a small thread-safety fix.
when dsp is destroyed, properly unhook itself from global space 
even if there is no probe.
also, a small thread-safety fix.


git-svn-id: c8e15679f62162744607fb5135e11e07de46de6b@574 ac7a513c-5e3a-0410-af42-968c3ac6e7dc

andrevmatos/psimedia,andrevmatos/psimedia