Changes to correctly save images

Ivans OSX machine didn't have scipy.imsave.
This workaround saves the images correctly.
Try to not use the PIPE

On OS X the script complains about too many open files.
Testing if that solves the problem.
Write image with name depending on selection

And also some other minor tweaks to the presenation, mostly for the
Alliance Meeting on Sept 19.
Changes to make it work on OS X

Also removing the STDOUT from the git-function broke the function on
Linux, so we're bringing it back...
Ignore OS X cruft correctly