dials.scale exclude_images widget

[dagewa]

The scaling step should provide access to the exclude_images functionality on the simple input tab. As it currently is in the advanced tab it is overly complicated to use. If I want to exclude image 74, I type 74 in the text entry box, but the job fails with:

Sorry: Exclude images must be input in the form exp:start:stop

Indeed the job runs if I enter 0:74:74 instead. DUI should be making this easier for the users (i.e. 3 labelled boxes and auto-fill the experiment id box)