Adding new files.
Adding $(DEFS), -lm, -DVERSION, -D_GNU_SOURCE
Integrated with GNU autoconf.

Fixed a bug where it would sometimes output a spurious overlapping track at end of file.

Changed default song length to 40s.
Minor revisions and elaborations to some sections.
ALSA arecord example doesn't need --file-type=wav (it's the default).

Added dropouts to s6.