[LAD] simulating analog audio devices part II

[Robin Gareus]

Hello again,

I've added libsamplerate for resampling/oversampling which - as expected
- dramatically improves the quality of the ngspice processed sound.

Here's some example 3sec guitar sound from current testing:
  http://mir.dnsalias.com/_media/oss/spicesound/git-fuzz64.mp3
  (left channel: resampled input-sound, right channel: fuzz-effect out)
  http://mir.dnsalias.com/oss/spicesound/examples#audio_example

The fuzz effect still sounds a little odd, but I believe that a
DI-recording would sound just like that ;) -  I have not progressed to
simulating tube-amps or synths yet.. lack of time, netlists and
tube-models; it's low priority ATM.

robin