HTML summary: Provides means to exclude generating test result files

This provides a switch and method for excluding the generation of the
test result HTML files (those that live under <testrun name>/). This
allows the user to trade some verbosity in the results for a significant
increase in generation speed. A run of quick.tests with all options
enabled takes ~5.5 seconds, with just pass and skip disabled it only
takes ~2.5 seconds. This only becomes more significant as more testsruns
are added the HTML page.

Signed-off-by: Dylan Baker <baker.dylan.c@gmail.com>
HTML Summary: Don't generate empty pages

Previously every page (fixes, regressions, etc) was generated regardless
of whether there was anything on that page. That is simply silly, this
patch does a quick check and only generates pages that actually have
content, and add those pages to the link bar at the top of the page.

Signed-off-by: Dylan Baker <baker.dylan.c@gmail.com>