Weird Gnuplot Information in Tutorial TravisCI

[coverney]

The following code snippet keeps showing up in the tutorial TravisCI log:

gnuplot> set terminal fig size 5,3.66 fontsize 10 background rgb "#ffffff"
                                                  ^
         line 0: unrecognized option

It doesn't break the tests but would be nice to remove. (Setting TASBEConfig to test mode doesn't seem to be working.)