Holy Bovines! It fscking works even with a moron at the keyboard! So,
this is the initial commit of a non-segfaulting implementation of
module-lfe-lp with an almost right LR4 biquad filter and a possibly
right rewind implementation. Still lacking code style fixes, those are
in progress.

Also, added another test wav file that is hides the initial "thump" when
the pulse sink unsuspends during mic testing. 

Thanks to TanuK for the help on this part.