Fixed envy24control to handle ADC volumes with higher resolution
properly.
Also, the bogus sync of gtk_adjustment between ADC and IPGA volumes
is fixed in the case no IPGA is detected.
* HW In level meters were broken
* The last PCM Out meter was broken
* S/PDIF channels can now be controlled with -s, --spdif
* The Patchbay/Router and Analog Volume tabs now accurately reflect the
number of requested channels in all cases.