various bits and pieces

First, thanks for this -- it's just what I was looking for and has worked very well on my home photo collection.

Here are loads of changes which I've made to get the script running on my photos.  However I'm fairly new to git and I realise (too late) I've not committed in a very helpful way.  So  if you would like to pull some of the changes but not all, and don't want to do the cherry-picking yourself, just let me know and I will make you a branch containing just the patches you select.  On the other hand if you want the lot, great (but I'm not done yet)!

Cheers

Graham