to life/lifesolver/nsip.hpp
* moved testsuite/test_ns_ipstab/ipStabilization.hpp
  to life/lifesolver/nsipterms.hpp

  to life/lifesolver/nsip.hpp
* moved testsuite/test_ns_ipstab/ipStabilization.hpp
  to life/lifesolver/nsipterms.hpp
* put class IPStabilization into subnamespace details

* modified preprocessor definitions for choosing the linear solver
* added possibility for using umfpack
* use boost matrix for umfpack and petsc
* added initialize function from file (restart, by M. Prosi)
* remove mean pressure only if appropriate (thanks to M. Fernandez)

Linear system options given from data file [mesh_motion/aztec]

added another way to retrieve some internal faces:
  now one can get all the (internal) faces (with the associated
  dof) that live on a given plane --defined by (a,b,c,d) s.t.
  ax + by + cz + d = 0.
working on putting all this into an external class.

* allow to set problem data from data file
* use uniform velocity instead of vortex
* handle boundary conditions (Dirichlet all over for the moment)
* do not fall in round off error trap for counting iterations
* save mass before and after reinitialization

* turned function sphere into static method sphere::phi

* small documentation bugfix

* access now private data members of HyperbolicSolver through accessors
* reformatted

* made all data private and provide const accessors where needed
* moved public CurrentFE& fe() from LevelSetSolver to HyperbolicSolver
* added protected non-const accessor to unknown function for LevelSetSolver

(protected _M_BCh_u -> private _M_BCh_fluid)

  in order to allow reinitialization to influence vectors in bdf
* initialize _M_t as well