TESTS: Decrease tests length

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
DESCRIPTORS: Minor member variable renaming in ASC

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

Fixes #4

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