intelli_plug: code review clean up

set def sampling rate to something sane rather than zero (instantaneous
rescheduling is not good if intelli_plug is disabled)

make touch input more generic rather than tied to a touchscreen driver

remove unused code

thanks to @dorimanx for the code reviews and suggestions

bump to version 2.3

Change-Id: I78ef6c44371004c0a6f6375743f4b67501f8fd61