small generalization: we can now interpolate data from abritrary
views (and not only from views having the same data type as the
destination)

I use this to interpolate (combination of) components of a field
in one mesh onto another mesh, for example a set of isosurfaces
from another field. Wicked cool! ;-)

small doc fixes

- generalized the octree code to make it work with all the element
types, and not only with triangles/tets (and fixed a couple of copy &
paste bugs in the process...)

- modified all depending plugins to take advantage of this

fix gcc warning

add comments

- renamed "Duplicate View" into "Alias View" (suggested by Philippe;
  less confusing since "Duplicate" implies that we actually copy the
  data, which is not what we are doing)

- added general "on the fly" tranformation matrix option. This allows
  for very efficient visualization of aliased datasets with
  non-destructive rotations, symmetries, etc.

help should mention that iView and ExternalView have to be of the same
type (scalar, vector or tensor)

new plugins: Gradient, Curl and Divergence

wring searchVector args

- generalized Plugin(CutGrid):
   * now works also for lines/points (i.e., when nPointsU and/or nPointV == 1)
   * new option ConnectPoints

- new Plugin(Eigenvalues)

- don't force color in Draw_PlaneInBoundingBox

fixed bug for multi timestep tets in searchScalar

- removed all the crappy STL code and rewrote it using JF's POLY_rep
  class

- generalized POLY_rep so that we can use the polygonal discretization
  as a surface mesh, and mesh in 3D afterwards. I.e., we can now take
  an input triangulation (a single surface in STL format, multiple
  surfaces in STL format, one or more surfaces defined using the new
  "Discrete Surface" commands), and generate a 3D mesh that uses it. We
  could in theory even mix triangulated and "normal" surfaces in the
  same geometry, but nothing is done at the moment to ensure that the
  mesh at the interfaces would match (if it does, it actually works
  very nicely)

- new STL mesh output format to export a surface mesh as a STL file

- added an option to the GEO output routine to save the surface mesh
  as discrete surfaces associated with the geometrical surfaces

- added STL and Text output formats for post-processing views (the
  text output allows for example to exploit plugin-generated data in
  gnuplot)

- generalized Plugin(Evaluate):

  * can loop automatically over all the timestep and/or components

  * can do operations using data from an external view

     - if the 2 views are based on the same grid, the plugin does the
       evaluation very efficiently

     - if the 2 views are based on differenet grids, the plugin
       automatically interpolates the external view data onto the
       grid of the current view

- added new Rand() function in MathEval

- default colormap is now # 2 (the Matlab "Jet" colormap)

Generalized the Levelset routines so that we can compute isovolumes with
all levelset-based plugins. This allows to extract either side of a
levelset (i.e., a half space with CutPlane, the interior/exterior of
a sphere with CutSphere, or the isovolume inside an isosurface with
CutMap).

use v0, v1, ..., vn to access the other components of the field

copyright update

- More intelligent way to detect if we need to apply a polygon offset
or not.

- better computation of translation coef in Draw2D

Added 2 options to control polygon offset. Instead of trying to guess
when a polygon offset is useful (it's no that simple when we combine
geo+mesh+some views), we just apply it conditionally to all surface
drawings.

fixed computation of Min/Max when the view contains different element types

Replaced all *non-modal* Fl_Windows with either Dialog_Windows or
Main_Windows, which are derived from Fl_Window amd correctly process
the OS-specific "Close Window" shortcuts (Pomme+W on MacOS, Alt+F4 on
Win32).

Small aesthetic changes:

- Only 'title-capitalize' window titles and menus; the rest should be
  capitalized like normal english sentences

- The window title should be exactly the same as the menu item
  (without the ellipsis character if there is one)

- reworked the keyboard shortcuts with Laurent (our very own Macintosh
  Usability Guidelines Expert)

- new smoothing option for jpeg output

- new small GUI dialogs for ps/pdf/jpeg/gif/msh output (makes the
  'format' menu in the file dialog much shorter)

removed unused extern

update docs

- cleaned up + generalized font selection
- generalized Plugin(Annotate) to allow font style selection for
  each text fragment
- fixed bug in per-view color selection

don't require gl2ps

missing line_width/point_size calls

clarify help

forgot to recompute the bbox

add a comment around a test copied as-is from the old Gradient plugin

merged Plugin(Lambda2) and Plugin(Gradient) in a single plugin, so that
we free up Plugin(Gradient) for future use

- plugin callbacks now draw their stuff until run/cancel is executed (so we
  manipulate the scene with the additional data displayed)
- made plugin code much shorter
- simpler defaults for StreamLines, CutGrid and Evaluate

draw points instead of grid

add callbacks to draw grid + fix interval definition