fix tetgen from Hang

interpolation (which prevent geo transforms on extruded entities)

Squeezed #if defined(HAVE_KBIPACK) preprocessor instructions only around
those parts where kbipack is really needed. It seems some homology fun
can be done without it when using coreduction algorithm.

- display all control points in GUI for gmsh curves
- uniformize Fl_Value::step() values in GUI

method to kbipack.

* hack for more stupid binary stl file headers

Begun writing ChainComplex class. Will have own file some day.

Also added an example file celldriver.cpp and transformer.geo
in /utils/misc

They construct a cell complex of a finite elemement mesh of a model,
and are able to reduce and coreduce it in order to compute model's
homology groups.

Also added contrib/kbipack to by Saku Suuriniemi for future use to
compute Smith normal forms of the boundary operator matrices of the
reduced cell complex.

Modified Makefiles and configure.in accordingly.

instead of implementation details (tetgen+delaunay & co)

- unstructured mesh algos (+ refs)
- interpolation matrices in .pos format

switch to Hang's new experimental version