SCRIPTS: Move 1st order pole-zero filter prototype into its own file

This will be useful to add various experimentation on this specific filter.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Actually implement the 1st order pole-zero filter

The previous version was suboptimal and not compliant with the doc.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Remove vectorized version of the 1st order pole-zero filter

Due to the fact that the scalar implementation in use was actually
not the good one.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Fix minor typo in comment

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Add a "fixed" version of 1st order pole-zero filter

This version has fixed coefficients that can be directly assigned,
including the zero coefficient (which is 1.0 in the base version).
This is an important step in the Moog filter: part of #18.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Make the 1st order pole zero filter pole coefficient settable

This coefficient has to be settable in order for the filter
to be a Moog base block.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Add a Moog dedicated file

Only the base lowpass filter has been prototype for now.
Fixes #18.

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