remove unused stuff + invert default sorting order in vis browser

forgot to classify vertex in STL reader

more on clcurv options

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

fix align

finished implementation of numeric+interactive visibility stuff for physicals

fix netgen optimization (need tets with neg vol)

allow unconstrained background meshes

more infrastructure for projection face gui

make numeric and interactive visualization tools obey the recursive flag

start visibility gui mods

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)

- re-add names in visibility broswer (will change in the future)
- shorten tutorials

better tol in extrude

show how to mesh the volume from a surface STL

don't throw in test_move_point_parametric_triangle

better tutorial on transfinite grids

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

remove more attractor crap