Improve 'Configure Displayed column' preferences for PDB interface

Geoff reported "when I have a lot of columns displayed the "Configure Displayed Columns" view is almost unusable since the tickboxes are always right-justified. Can we left justify them so they are next to the PDB field descriptions. It might be easier just to put them to the left of the descriptions rather than to the right."

He also suggested that the options should be grouped according to: quality measure, cross references, description of experiment etc.