FGCom-mumble compat: Glass version not support very good

[hbeni]

• When the "FGCOM-mumble" integration box is ticked from the aircraft menu, you cannot select the MIC form the Audio panel.
• Volume on COM1 does reset to 0.7 after a short while when deactivating COM1 in the audio panel
• Volume on COM2 stays on 0.0 always (regardless of the box)

(should test wether the C182 is also affected)

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Reproduce:

• enable "DBG" button in FGCom-mumbles settings dialog to see the protocol fields
• play around with the radios. See the values not changing correctly for the protocol (protocol reads instruments standard properties)

[hbeni]

C182 investigation showed also issues, albeit other constellation:
HHS81/c182s#614

[hbeni]

Also, the KMA20TSO is not documented in the wiki; I think it might be a good idea to write up some doc showing how to use it.
For real radio usage it is somewhat irritating that with the selector witch to OFF and AUTO enabled, you cannot hear the other radio but just the one selected by the rotary switch (but thats realistic)