* CH_10 is on APM2 pin A10 (based on A1..A8 convention)
* CH_11 is on APM2 pin A11
* Only the code in enable_out, disable_out, and OutputCh needed to change.
* CH_10 and CH_11 always have an output period of 20ms (50Hz).
* Every use of MSK_CH_n changed to _BV(CH_n)
* Easier to read, and will allow CH_n to be parameterized without needing
a separate macro expansion for the MSK value.