- fix bb computation to avoid model jumping around when adding points in z=0 plane
- pass interpol matrices as ref

removed parFromPoint and closestPoint from GEdge; replace their use in
cgns code by appropriate reparamMeshVertex calls (not tested: I don't have
cgns)

removed now unused golden section minimizer (brent), now unused

API cleanup: new discreteVertex, discreteEdge, ... entities (replacing
the old hacks in gmshVertex, gmshEdge, ...), the future basis of the
indepedent "null" model (cf. HAVE_NO_GEO define)

API cleanup: removed unused functions

- implemented all missing 2nd order representations
- removed unused member functions in GFace + cleaned up GFace::point

fix interactive modification of mesh attributes

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

start opencascade integration