Snd 16.5

Kjetil Matheussen added the --with-webserver configuration flag to Snd, and
  made all the supporting changes.

Daniel Hensel sent instructions to build Snd in OSX -- see README.Snd.

ttaenc removed: it appears to be dead (no movement in 10 years), or infected.

changed spectr.scm to export only *spectr*, rgb.scm *rgb*.

checked: sbcl 1.3.4|5, gtk 3.20.2|3 3.21.1, gsl 2.1

Thanks!: Greg Santucci, Daniel Lopez, Kjetil Matheussen, Daniel Hensel
