start reducing header pollution (removed Gmsh.h + cleaned up GModel & co)

	-) A bug has been corrected in the MeshAdapt Procedure
	-) The 2D Delaunay is now Anisotropic
	-) 3D Sliver removal procedure has been improved
	-) Curvilinear mesh generation has been slightly improved,
	   even if it is still far from done
JFR

Removed the "search around point" strategy when we provide a background mesh.

(Now that we can have several fields, it's much better to specify another default
field for when a search fails.)

Detect when we have zero lc and fix it (+ send an error message)

moving to new post-processing database

                    *** WARNING ***

do not upgrade if you need plugins or adaptive views: these have not
been ported (yet) to the new database

                    *** WARNING ***

fix logic for unconstrained bgmesh

cleanup

- only save mesh vertices that are used by elements

- fix warnings + indent + memory leaks in new Field classes

- temporary fix to avoid crashes in new field manager when post-pro
  views are reloaded or removed at run-time

background mesh. I've still to write some fields sub-class, but backward
compatibility should be ok now.
Jonathan
----------------------------------------------------------------------

we use the Lawson algorithm for 3D surface and the smallest circumsphere
of the triangles as circumcircle.

JFR

better logic (fix bug where we could not get grids coarser than CTX.lc/10)

enhancement of gmsh Surfaces

JFR

corrected some bugs in 2d mesher & occ interface

fix logic + crashes w/ bgmesh on file

removed gobal meshSize in GMODEL: for now use CTX.lc, which is correctly
updated when multiple files are merged

- reimplemented subdivision of extruded meshes
- fix indent + unused var + gcc warnings all over the place

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

allow unconstrained background meshes