VCA: Add asserts based on synth max allowed ADSD parameters duration

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SYNTHESIZER: Rename "Q Factor" to "resonance"

This is part of hiding the implementation to the user - resonance being
more general than Q Factor.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
VCF: Add filter contour feature to the VCF

This is part of #74.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
BUILD: Fix missing include directory

SoundTailor header files may be required within implementations.
This may have to be fixed later, however currently the better
alternative is to expose SoundTailor headers in various implementations.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SYNTHESIZER: Remove useless Release parameter setter in Vca/Vcf

Since the current synthesizer uses an Adsd model, there is no release
parameter.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
VCF: Fix a typo in asserts

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SYNTHESIZER: Add parameters and management for filter contour feature

This is part of #74.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>