rewriting internal GMI models with proper topology

agm.h / agm.c contain the implementation
of the CAD model topology structure
plus a simple mechanism for model tags.

gmi_lookup implements tag-based lookup,
using binary search for frozen models
and linear search otherwise.

gmi_base is an agm struct plus a gmi_lookup struct,
and most gmi_mesh functionality is merged into gmi_base
(there is just one .dmg read function again).

gmi_analytic has new functions for reparam.

this passes the test suite, at least.
Merge branch 'master' of https://github.com/SCOREC/core
pkg-config: ma depends on parma and zoltan
fix add_analytic for low dimensions
fix a couple bugs in gmi_analytic code
remove the convenience function for edge reparam

it is best to do this out in user
code with the general function.
the idea of double*'s was not that great.
adding Fan's multi-spline test
Merge branch 'master' of https://github.com/SCOREC/core