change y,-y to have the axes the same way as for x,-x and z,-z

don't optimize transfinite volumes!

trying to fix the transfinite volume bug introduced by the 'left' and
'alternate' transfinite surface changes made a while ago

fix stat print for pyramids

new shortcuts for alternative x, y, z views (still needs to be completed by dave)

forgot to indent these two

- the fltk m#@!er f*!@ers changed the way FL_CTRL/FL_META shortcuts
are treated on the Mac. This patch forces FL_META (the "Apple key") for
all Ctrl shortcuts in the menu. I think this is the way most people on
Macs would expect the shortcuts to work anyway.

- fix metis readme+configure info

update tetgen to latest version 1.3.4

upgrade triangle to version 1.6

prepare for 1.61

disable applyOptimizationPatterns for now

quick hack to get lighting of element edges (not perfect and rather slow
but good enough for me for now)

shorter intro

include metis in the free version since we now have Karypis' approval

tweak automatic polygon offset check

make "BoundingBox{x,X,y,Y,z,Z}" actually do what the documentation claims
it does

The current behavior of Gmsh when drawing 3D scalar fields is not coherent
with what is done in 2D: to draw filled iso-values or continuous maps in 3D,
we should ideally do volume rendering. Right now we draw the iso-values
(i.e., surfaces), which is both not coherent with the definition of
continuous maps or filled iso-values, but is also annoying when trying to
visualize fields that are constant per element (since in that case nothing is
displayed!)

Until we can do volume rendering, I've changed the behavior to draw the
solution on the boundary of the 3D elements. It's rather slow, but it's the
right thing to do visually.

print 1D elts in unv format + fix 2nd order 1d elts in unv format

indent + cleanup messages (somewhat)