Inductive Sensor Mount for 'P3steel - toolson edition MK2'

Inductive Sensor Mount for toolson's P3Steel MK2.

The STL files for the MK2 are unfortunately not available on Thingiverse, but you can find them here: http://scheuten.me/?page_id=708

The sensor is a typical LJ12A3-4-Z/BX with NPN logic.

Set these values in your Marlin Configuration.h file
```
#define X_PROBE_OFFSET_FROM_EXTRUDER 30
#define Y_PROBE_OFFSET_FROM_EXTRUDER 30
```