Initialize all axis as absolute at the beginning.

Firmware/Marlin_main.cpp

@@ -178,7 +178,7 @@ float default_retraction = DEFAULT_RETRACTION;
 
 
 float homing_feedrate[] = HOMING_FEEDRATE;
-uint8_t axis_relative_modes;
+uint8_t axis_relative_modes = 0;
 int feedmultiply=100; //100->1 200->2
 int extrudemultiply=100; //100->1 200->2
 int extruder_multiply[EXTRUDERS] = {100