python: Path: *.py: Fix python3 syntax

src/Mod/Path/PathScripts/example_pre.py

@@ -60,7 +60,7 @@ def insert(filename,docname):
             
 def parse(inputstring):
     "parse(inputstring): returns a parsed output string"
-    print "preprocessing..."
+    print("preprocessing...")
     
     # split the input by line
     lines = inputstring.split("\n")
@@ -93,9 +93,9 @@ def parse(inputstring):
             # no G or M command: we repeat the last one
             output += lastcommand + " " + l + "\n"
             
-    print "done preprocessing."
+    print("done preprocessing.")
     return output
 
 
-print __name__ + " gcode preprocessor loaded."
+print(__name__ + " gcode preprocessor loaded.")