ok. so you kept #define Z_PROBE_SWITCHING_DISTANCE at 20?

I'm sorry to contradict you but this  #define Z_PROBE_SWITCHING_DISTANCE 20 does not work ...

#define ENABLE_SOFTWARE_SPI_CLASS 1

#define Z_PROBE_SWITCHING_DISTANCE 20

#define XAXIS_STEPS_PER_MM 80

#define ENDSTOP_Z_BACK_ON_HOME 0

#define CONFIGURATION_H

#define CONFIGURATION_H

#define FAN_PIN           4

#define INVERT_Z_DIR 1

Sorry I forgot to mention I fixed the sensor triggering by changing #define MIN_HARDWARE_ENDSTOP_Z from true to false and again when I home Z my bed goes downwards.

#define ENDSTOP_PULLUP_Z_MIN true

#define Z_PROBE_X1 20

I tryed #define ENDSTOP_Z_MAX_INVERTING false, but then when I home Z, bed moves downwards a bit and then stops.

#define ENDSTOP_Z_MAX_INVERTING false should be true like the other physical endstops.

2. If I try to change the #define NUM_EXTRUDER to 2 I get many compiling errors (I attatched the file with the errors). 

ie if I activate the auto leveling with #define BED_LEVELING_METHOD 0 I get this result:

/* Normal core xy implementation needs 2 virtual steps for a motor step to guarantee that every tiny move gets maximum one step regardless of direction. This can cost some speed, so alternatively y

#define USER_THERMISTORTABLE0 {{0,2400},{0,2320},{0,2240},{0,2160},{0,2080},{0,2000},{0,1920},{0,1840},{0,1760},{0,1680},{0,1600},{0,1520},{1,1440},{1,1280},{2,1120},{3,960},{9,640},{44,320},{287,0}}

#define ENABLE_BACKLASH_COMPENSATION 1