orientation bug in extrusion

- make it easier to build universal binaries on Mac
- remove unused arg in transform functions (an prepare the terrain for periodic meshes)

- added warning dialog before attempting to append a scripting
command to a non-geometry file

- fixed mean plane computation for periodic curves

- added headers + ramn indent on Attractor files

enhancement of gmsh Surfaces

JFR

fix shift/reduce conflict in parser (had to slightly modify embedding syntax)

corrected some bugs in 2d mesher & occ interface

- save physicals labels when saving unrolled geometries
- fixed crash in unrolled geo save (discrete points)
- Delete Physicals now also deletes the physicals in GModel
- removed unused rules and terminals in parser
- put at least one mid-point when meshing non-straight lines
  in OCC: this fixes most of the trivial 2d meshing problems

removed most unused, untested or non-working stuff in old CAD code

- bug fix: need to create temporary bounding box and compute CTX.lc
*during* parsing step until we fill the new db on the fly

(Some geo transforms in the parser use CTX.lc for tolerences. But
CTX.lc was always equal to 1 since we only do a SetBoundingBox on
GModel after parsing!)

- cleanup spline interpol (remove duplicate code)

OpenProblem -> OpenProject
MergeProblem -> MergeFile

Layers{N,1} can now be written simply as Layers{N}

deprecated -> warnings instead of errors

make default transfinite subdivision match old version to minimize
backward compat problems

new option to compute char lengths from curvature + removed most unused mesh options

curvature control is ok
divide and conquer algo has been cleaned up

more infrastructure for projection face gui

physical entities can now be defined using a string instead of a number (and
there is a new field $PhysicalNames in the .msh format to keep track of these
strings)

remove elliptic - same as Transfinite with Mesh.Smoothing > 1

- finished volume extrusion
- cleanup ExtrudeParam (plug memory leak + remove unused stuff)
- make netgen the default 3D algo for now (since it actually works)

make explicit regions in extrusions DEPRECATED

cleanup

bidir db: phase 3 -- move all the old geo stuff into Geo/

bidi db: phase 2 -- continued

bidir db: phase 2 -- removed all (well, most of) the old data structures and
algorithms

bidir db: phase 1

- add compatibility syntax for getdp (string~{fexpr})
- add possibility to write/append to files with Printf

merging offscreen rendering from branch