Fix for broken 2D plots in fltk after 'axis tight'

[logari81]

Hi,

during our discussion about the aspect ratio improvements we have found
out that demo("axis",5) is broken on the fltk backend. This is because
actually when using the fltk backend for 2D plots, "axis tight" will not
work at all. The attached changeset fixes this problem.

BR

Kostas

P.S. we continue our discussion about aspect ratio related issues in the
other thread, use this thread only for comments related to the attached
changeset.

axistight1.changeset
Description: Text document