Story 3084: [RefRed] Enable more complex background subtraction

Rearrange background

Main Window

Single Plot Window

Plot2D Window

SF Calculator

The SF Calculator can't process two backgrounds for the moment, thus it's excluded from this pieces of work.

The position of the boundary lines updating with the spin box arrows

Background dialog

RefRed wrongly starts with NORMALIZATION tab as current

Unable to change to DATA tab even after selecting a row in the reduction table