EPM ch7 ch8 support with logging

todo: fix disabling external led correctly
The following has been taken care off
1.   looks like the EPM_PIN_1 != -1 is being checked twice in a few places when the intention was probably to check EPM_PIN_2
2.    it would probably be better to use ch7 or ch8 instead of ch6. Ch7 and 8 also support 3 positions.
3.   looks like your editor is indenting 2 spaces instead of 4.
4.    we should implement #defines so that it can be left out of the compile (we're doing this for all new features because we're running out of flash on the APM2). I can take care of this.