* device/include/pic16/adc.h,

* device/include/pic16/adc.h,
  device/lib/pic16/libio/adc/adcbusy.c,
  device/lib/pic16/libio/adc/adcopen.c,
  device/lib/pic16/libio/adc/adcsetch.c: support old 18f242 and new
  18f2455 style ADC devices, based on patch #1776197
* device/lib/pic16/libio/adc/adcclose.c,
  device/lib/pic16/libio/adc/adcconv.c,
  device/lib/pic16/libio/adc/adcread.c: cosmetic changes
* device/include/pic16/{pic18f2331.h,pic18f2431.h},
  device/lib/pic16/libdev/{pic18f2331.c,pic18f2431.c}: reuse 18f4331
* device/include/pic16/pic18f4431.h,
  device/lib/pic16/libdev/pic18f4431.c: remove outdated comments
* device/lib/pic16/libio/adc.ignore: forbid unhandled devices

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@5150 4a8a32a2-be11-0410-ad9d-d568d2c75423