Added faster soft limits check for arcs when work envelope is a cuboid, fixed some related obscure bugs.

New/modified core entry points for soft limit checking.
More delta robot tuning, added setting warning in $DELTA output if some settings are inconsistent such as steps/rad, acceleration etc.
Fix for issue #361, HOME status is not reported or reported late when auto reporting is enabled with setting $481.

plugins_init.h

@@ -78,6 +78,11 @@
     lb_clusters_init();
 #endif
 
+#if PROBE_PROTECT_ENABLE
+    extern void probe_protect_init (void);
+    probe_protect_init();
+#endif
+
 #if WEBUI_ENABLE
     extern void webui_init (void);
     webui_init();