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/patchRelease.py

@@ -1,10 +1,9 @@
 #!/usr/bin/env python3
 
-from  __future__ import  print_function
 import releaseCommon
 
 v = releaseCommon.Version()
 v.incrementPatchNumber()
 releaseCommon.performUpdates(v)
 
-print( "Updated Version.hpp, README and Conan to v{0}".format( v.getVersionString() ) )
+print( "Updated files to v{0}".format( v.getVersionString() ) )