update comments
cosmetic
change bit-depth of some integer types and use definitions from stdint.h
remove module_adc_common dependency
fix client request handling (channel communication problem because data
width was interpreted differently on client and server side)
add missing stdbool_xc.h
rearrange stuff in adc_ad7949_dual_singleshot() in order to reduce
processing delays between outputs (adc data will be garbage in case we
miss some ticks of the port clock)