This reverts commit dafeac01d8f14162600cf821404ba4072dcae14d. ADC will be disabled on APM2
enable_channel() must be used before the Ch6() method is called to enable gathering of data on the required channels
this abstracts the way of getting inertial sensor (gyro and accelerometer) data for the APM1 and purple hardware. The Oilpan code is based closely on the old APM1 code