FM demodulator improvements

* Bugfixes
* Improvements to make deviation measurements more exact
Receiver deviation calibration improvements

* Now applying a flat top window before the Goertzel to make the
  amplitude measurements more accurate when the tone being measured is
  not spot on the frequency or the tone period length does not match the
  Goertzel block length.

* The Goertzel bandwidth was widened from 10 to 20 Hz to better handle
  inexact calibration frequency.

* Printing deviation four tims per second instead of ten.

* Forcing DTMF_MUTING to off so that it will not interfere with the
  measurements if using DTMF for calibration.
Now using the same splatter filter in both the Tx and the Rx.
NetTrxAdapter: New config variable RX_SIGLEV
Merge branch 'afsk_com' of /home/sysop/svxlink into afsk_com
Licence for Aladdin Enterprices md5 stuff is Zlib
Merge branch 'master' into afsk_com

Conflicts:
	src/svxlink/trx/LocalRxBase.cpp