moved print to stderr to logger function

* monkey patching logger will replace the print to stderr functionality instead of supplement it

Author: Will Silva

dronekit/util.py

@@ -3,9 +3,8 @@
 
 
 def errprinter(*args):
-    print(*args, file=sys.stderr)
-    sys.stderr.flush()
     logger(*args)
 
 def logger(*args):
-    pass
+    print(*args, file=sys.stderr)
+    sys.stderr.flush()