mainly added 3D support,  E1 tetrahedra only for now
* mesh read and .vtk writing of solution
* solution of Poisson problems with test_assem3d.c
* multigrid for E1 is working
* interface with mesh generator gmsh
  + can directly read .msh files
  + can use a modified gmsh to project new nodes onto geometry
* adaptivity in 3D:
  + still only Poisson equation
  + ZZ error estimate (generic)
  + Baensch green refinement
* several 3D geometries for tests

Improvements on Navier-Stokes preconditioner:
* implemented Chebyshev semi iteration in the preconditioner for
  Stokes problems. This does indeed allow significant savings. Should
  investigate this further.* new interface to hypre->BoomerAMG:
  + algebraic multigrid
  + requires hypre to be configured and built without MPI
* Option to use AMG inside Preconditioner for navsto
  + select  FP_VELOCITY_SOLVER (4)  in feins_macros.h to use this 

Other improvements:
* improved OMP implementation on some parts
  + convection-diffussion code is now OMP parallel
