Cleanup the helper scripts

* Remove from __future__ import print_function, because we
  no longer support Python2.
* Clean out unused parts of tools/scripts/scriptCommon.py
* Move appveyorMergeCoverageScript to Python3
* Update user reporting in *release scripts
* Cleanup module imports

tools/scripts/releaseCommon.py

@@ -1,10 +1,6 @@
-from  __future__ import  print_function
-
 import os
-import sys
 import re
 import string
-import glob
 import fnmatch
 
 from scriptCommon import catchPath