As @jcfr showed in #230, the progress reporting can be simplified, requiring the user only to specify one variable that holds a progress reporter.

Update PyRadiomics to this implementation and add examples for both use with `tqdm.tqdm` (which can be used directly) or `click.progressbar` (which requires a simple wrapper class). Examples are provided in both the helloRadiomics script and notebook.

Progress reporting in full-python mode in GLCM and GLSZM now uses a progress reporter that is instantiated with an interator (as opposed to a length) and uses this progress reporter in the loop to iterate over the gray levels. This is encapsulated in a `with` statement to ensure correct closure.
Finally, a dummy progress reporter is provided for the cases where no progressbar is needed (none specified or verbosity level > INFO). In those cases the `_dummyProgressReporter` (defined in `__init__.py`) is used, which accepts the arguments from PyRadiomics and iterates over the gray levels passed in the iterable, but does not report any progress back to the user.