add support for "growing" 3D spheres

new drawing cide complete (except for LCM tensor stuff--needs to be rethought
anyway)

need testing

added full supprt for tapered cylinders + make sure we have a normal for
all lines

bug fixes + add 3D lines/points

CatMullRom->Spline

add bit of code to intersect curves with a surface (allows to do "poor man's"
trimmed patches ;-)

store vectors in "pseudo" vertex arrays to avoid looping over elements
in the drawing loop

reworked solver gui

- removed static GMODEL (can now have multiple models)
- added infrastructure for new post-processor module

add translation along principal axes

- better SplitFileName (e.g. to remove full path from
  \includegraphics{} in .tex files)

- better interactive positionning of projection surfaces

Updating Gmsh to use new, "external" version of FourierModel.

moving FourierModel to its new home :-)