Fix for a Python3 bug in cl_get_and_test.py
* Fixed a bug regarding cl buffers for atomic reductions in cl_launcher
* Fixed the bug where local pointer variables in an atomic block could be
assigned to variables outside the block

Updated cl_check_results.py: takes some .csv files and produces a html file,
containing a table for easily identifying non-conforming results between
different test platforms. It can take one argument, representing the relative
path to the folder where the .csv files reside (the resulting html file will
also be generated in that folder).