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 :-)

typo

pretty

more IO work

more IO work

remove extra includes + add small routine to read params

more FM IO

added selection filtering

more work on fm

make remove() routines safe

more fm work