Small corrections for ONFILE background meshes:

- should now work reliably interactively (and not only the first time
  the view is applied as a background mesh)

- fixed some memory leaks

added a couple of nice examples

1.52

Only enable POLYGON_OFFSET_FILL for volume faces if we draw the
edges. Otherwise it looks pretty bad since we draw connected faces
with large differences in orientation.

reverting to old rpm build method

build source rpm, too

add volume test for 2nd order tets in UNV format, too

- enable lights by default
- remove obsolete comments about MergeWithBoundingBox

Fixed orientation of polygons produced by CutTriangle2D so that we can
use a TWO_SIDE light model everywhere. This also fixes the ugly "checkboard
patterns" when using custom scales on continuous maps.

removed unused variables

Simplified the way we deal with View.Raise: instead of trying to be clever,
let's just use coord += raise * value. This is far more predictable and
matches the behaviour of the plugins.

use default line width to draw bounding boxes and axes

wording

draw string with min/max of the bounding box (very useful when we have no
geometry points to check the coorrdinates from!)

added comment about unknown origin of the code

Removed General.MovingLight option (confusing, and never really worked
anyway)

pretty print

add a bit more space between y-axis and labels

pretty print

pretty print

pretty print

set default position of 2d graphs 20 pixels more to the right

pretty print

- cleaned up the octree code (renamed some files, added copyright
  notices, indented everything)

- backported JF's doc from the texinfo file into the c++ code (the
  documentation is actually generated automatically by Gmsh with
  "gmsh -doc"!)

- replaced nPoints with nPointsU and nPointsV in CutGrid

- fixed a couple of printfs + removed some unused variables

- added new General.GraphicsFont option

- added GUI stuff for font selection, quadric subdivisions, selected
  lines

- improved Graph2D's handling of fonts

- removed Print.EpsFont and Print.EpsFontSize options

refined arrow editor

adding test-case where 2nd order algo generates hanging nodes

Merged options->general->light panel into options->general->aspect. This
is more consistent with what we do in options->geometry and options->mesh.