MISC: Ignoring one more common build folder

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SYNTHESIZER: Moved interpolation stuff

Now having a common source file for interpolation stuff - this should
probably be moved later into a dedicated section, the same as generators.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SYNTHESIZER: Added a round function

C++, eleven C++11, still does not have that.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
TESTS: Using an explicit method to close the debug stream

This allows to close it sooner than the object deletion.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
TESTS: Minor comments fixes

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Moved a few functions into a dedicated common file

Creating a new "utility" file for cleaner test scripts.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SYNTHESIZER: Added a new Interpolator object

This is a generic object for interpolating from a given data buffer.
The interpolation function itself is a (template, e.g. compile-time)
parameter.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
TESTS: Added a specific test source file for the interpolator

For now, only testing the 1st-order linear interpolation in "passthrough"
configuration (e.g. ratio = 1).

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Added a sandbox script file for Interpolation

This will allow to test various configuration and interpolation methods.

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