use homogenous coordinates so that we can apply translations, too.

- First draft (pretty much untested!) of new "Integrate" plugin to
  * integrate scalar fields over all the elements in a view
  * integrate the circulation of vector fields along line elements
  * integrate the flux of vector fields across surface elements

  Used with Plugin(DisplacementRaise) and Plugin(Evaluate) this
  permits for example to compute the area/volume of deformed
  configurations; and, with Plugin(CutPlane)+Plugin(Skin), the
  perimeter of deformed sections. Another interesting application is
  to use it on a vector field with Plugin(CutPlane), in order to
  compute fluxes across arbitrary cross-sections.

- Added "connectPoints" option to Plugin(CutParametric) so
  that we can feed its output to Plugin(Integrate)

- Added Normals and Tangents options to visualize the orientation of
  elements in post-processing views

- Added "swapOrientation" in Plugin(Transform) to change the
  orientation of the elements (in place) (+ moved the transformation
  routines from the view class into the plugin)

- fixed #defines in some of the plugin header files

secured most of the list_pointer accesses

Added automatic documentation generation for plugins

Update copyright notice

- new DecomposeInSimplex plugin
- new "Combine Views" command in the parser
- cleaned up View::tranform and View::smooth (+small bug fix for SLs)
- better check for transparency sorting
- make depend
- new View.AlphaChannel option to change the transparency
  globally for a given view (instead of having to change the colormap
  by hand every time)

With all the above, we can now generate very nice (and correct)
transparent iso-surfaces:

Merge "../tutorial/view3.pos";

minIso = 0;
maxIso = 2;
nbIso = 7;

Plugin(CutMap).iView = 0;

For i In {1:nbIso}
  Plugin(CutMap).A = (maxIso-minIso)/nbIso * i;
  Plugin(CutMap).Run;
EndFor

Delete View[0];
Combine Views;

For i In {1:nbIso}
  Delete View[0];
EndFor

Plugin(DecomposeInSimplex).iView = 0;
Plugin(DecomposeInSimplex).Run;

View[0].AlphaChannel = 0.6;

Say if the plugin is executed in-place or if it creates new views

Big Levelset rewrite (+ cleanup of all other plugins).

Not finished yet, but I need to commit this now so that I can use it
with the boss tomorrow at work.

This version should compile and have all the old features working,
plus some extras (levelsets of scalar/vector/tensor 1D, 2D and
3D simplectic views).

JF: 'Plugin(XX).Save' is now deprecated. Use 'Save View[XX] "filename"'
instead.

typo

Reworked the help strings for all the plugins. Easier to understand,
now, Sean? :-)

Fix whitespace in copyright headers

Indented all source files using utils/gmshindent

Updated copyright