Improve UI of Assign weights by pairwise comparison tool

[DuncanHornby]

The Assign weights by pairwise comparison tool allows you to create weights for variables through the interactive comparison matrix as shown below.

My ideas for this interface are:

1. Allow user to drag and resize the comparison matrix interface, currently it is locked to a single position which seems to be on top of the geo-processing tool.
2. The sliders are fiddly, along with the sliders it would be nice to be able to type the relative importance in as dragging the slider can be inaccurate.