Fixing bed extruder crashing on GT2650 firmware| Rostock G2s

[liankary]

As I found out, the crashing to heatbed was caused by inverted axis direction, and setting these AXIS_%_DIR to false solved the problem. I redesigned configuration.h a bit to make it easier to set up some constants, so make sure to use it!

PS I'll upload final verion of Marlin probably in few days

PSS //from Configuration.h

/* AXIS INVERT BLOCK FROM LINE 365 */
/* better not touch these */
#define INVERT_X_DIR false //
#define INVERT_Y_DIR false // <= GT coders pl0x, these were set to "True" (Sic!)
#define INVERT_Z_DIR false //
/*=== End of better-not-touch-these area ==*/

[Mark]

When did the crash happen? Did it happen after the command G29?