Axes Ticks Positioning in 3D plots (FLTK)

[logari81]

In the attached patch I have modified the positioning of axes in 3D
plots, in order to make it more compatible with ML. The current behavior
of octave without my patch is shown in the attachment
"axes-ticks-unpatched.png". The new behavior after applying my patch is
shown in "axes-ticks-patched.png" and corresponds to the behavior of the
ML version (2010a) that I have access to.

An extra feature that I have included in this patch is switching to
"tick_along_z" mode for elevation angles less than 5° (it seems that ML
uses this criterion as well).

Please test this patch for possible regressions.

BR
Kostas

P.S. A prerequisite for the attached patch is the following:
https://savannah.gnu.org/support/download.php?file_id=22377
which is also waiting to be tested/committed.

axes-ticks-positioning.changeset
Description: Text document

axes-ticks-unpatched.png
Description: PNG image

axes-ticks-patched.png
Description: PNG image