Output directory less messy, moved some stuff to sysutil

The output directory creation hopefully makes more sense now
Added a user query for directories with the same name as the one
that is going to have images put into it. Can now skip processing of
certain directories.
Switches for modelLearner, name of param hierarchy changed

modelLearner now has switches -b and -o, which can be used to specify
that all files to be processed are background (-b), and to specify the
location to which the YAML file will be output (-o). The learner
also automatically considers directories with name "background" to
contain background images. Images in this directory, and all images
during runs with -b will not be thresholded before processing. All other
images will be thresholded in order to remove the black pixels.

Changed the param hierarchy top level name for the models to /models to
reflect the fact that the background model also sits there. Also separated
out the background model from object models.
Merge branch 'objlib' of github.com:DD2425-group-5/vision into objlib