(Re)introduce progress bar

A progress bar was originally implemented with ezcConsoleProgressbar,
but this was removed by commit 31d5d775f8bedb6a189ed8289047c3d87b04e7e4

This commit re-introduces a progress bar using Symfony\Component\Console\Helper\ProgressHelper
Made the progress bar optional (disabled by default) with option --progress
Basic implementation of exporting PHPDCD result as HTML report
Switched to Twig
Moved html report to Twig, with Bootstrap styling and client side table sorting
HtmlReport: added some totals (dead functions, total LOC and file count)