FreeSWITCH

FS-9542 [avmd]: multithreaded

Now avmd detection is done in detector threads
processing audio frames with different resolution
and/or offsets. Detection decision is based on relative
standard deviation which dynamically adjusts to the signal.
Detection of amplitude, frequency and both simultaneously
is enabled and corresponding setting added to the configuration.
Frequency estimates are filtered with median filter.

This commit also resolves:
FS-9539 - Get estimates with different resolution
FS-9513 - Use adjustable thresholds
FS-9502 - Add detection mode setting
FS-9501 - Enable three modes of detection
FS-9407 - Add check of amplitude for NaN before appending to SMA buffer
FS-9139 - Unit test framework