saugns v0.3.3. Wave type changes. Internal reworking.

Wave type changes (rebased down to v0.2.14):
 * Use an anti-aliased cycle for the 'sqr'
   LUT, removing low-frequency noise, but
   still a bit rough; the new sound lacks
   full "bite" at low frequencies.
 * Do the same for the 'saw' LUT, with
   the same quality improvement (but a
   bit more "bite" preserved). The slope
   is now decreasing instead of increasing
   (can be changed with neg. amp. or freq.).
 * Remove 'shh' type
   (very similar to old 'saw').

Internal design change in preparation
for future work, without functional change.
This tag has no release notes.