A few things for TAS when testing

[granrothge]

• - M. Lumsden saw the experiment file names, but only saw 403 errors rather than plots.
• - On the fitting tab, it should default to the default x rather than pt on the x axis
• - Even if I change the X axis to something other than pt it does not fit properly with that axis.

[ricleal]

• When fitting, the first plot should be the default x /y. When plotting more plots, they should follow the default axis of the first plot. If the axis are not the same default, we should show a warning: "The default axis are different. The default axis are ....".