New FFT initialization functions to make it easier for the linker
to optimize the code size when the library is used as a static
library and can't be rebuilt.
Compilation directives for code size optimizations have been removed.
arm_cmplx_mag_q15 reworked to be more accurate but less efficient.
New function arm_cmplx_mag_fast_q15 introduced to retain previous
(less accurate) but faster behavior.
Improvement to Python wrapper to support the new functions.
Christophe Favergeon