TODO

- something to do a scatter-plot of patches in a colour chart for Joanne

    useful for assessing accuracy and comparability of images taken
    with various UVL setups

- centre 50% of patch is too much in some cases

    add a control to let users pick the size of the patch that gets
    measured, plus a simple visualisation to show where the
    patches are falling

	Done 

- in "align" tab, A2 does not update correctly

    investigate

    	Need to do a "reset" on almost everything in the "align" tab when we
	clean it out

- try to stop tab double-click creating a new tab

- add UVL before stray-light removal to "results" tab

	Done

- fix typo in "results" tab, column C

	Done

- need a control for UVL exposure compensation

    eg. set white brightness from UV innovations white

	Added "exposure compensation" column to the end of uvlstray