Defined the +-* operators on Pointf.

Removed the deprecated VibrationLimit feature.
Added triangle infill.
The Prusa3D fork of Slic3r has been marked as "Slic3r Prusa Edition"
with menus pointing to the prusa3d/slic3r github release page
and Prusa3D drivers downloads page.

xs/xsp/XS.xsp

@@ -22,4 +22,10 @@ DEBUG_OUT_PATH_PREFIX()
         RETVAL = newSVpv(SLIC3R_DEBUG_OUT_PATH_PREFIX, 0);
     OUTPUT: RETVAL
 
+SV*
+FORK_NAME()
+    CODE:
+        RETVAL = newSVpv(SLIC3R_FORK_NAME, 0);
+    OUTPUT: RETVAL
+
 %}