Load His Master's Noisetracker wavetable samples

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Code cleanup: remove unused lines

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Add support for His Master's Noise synth

Generalize instrument extras support to support both MED and HMNT synth
sounds. Add HMNT synth to sequence waveforms according to what's defined
in the waveform sequence table. Rename fest_load to hmnt_load to be
consistent with hmnt_synth.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>