Use the get_runs from htsworkflow.pipelines.runfolder

Use the get_runs from htsworkflow.pipelines.runfolder
On the plus side this means it'll handle IPAR files, on the downside
it means that the srf program will crash if there's something wrong with
the summary.htm file or if there's an ipar directory that doesn't have
a run in it.
(I really need to add some code to get_runs to skip over IPAR directories that
are being ignored.)