@dolleg fix issue #154, update issue #149
differentiate 3.4 with previous petsc/slepc releases
start working on dirac integration
update issue #155
label elements that share a point, an edge or a face with the boundary and not
only a face
now boundaryelements returns an iterator range over these elements
@mszopos @ranine update issue #155
compute integral of normal derivative either directly or using residual (using
boundary elements)
the results are quite interesting and the residual formulation is much more
accurate, however investigations are still necessary.
At the moment the ROC is 6 for the P1 and P2 formulations and 1 and 2
respectively for the direct computations of the integral of the normal derivative
use loadMesh() now
see commit regarding options for gmsh.domain
added options for gmsh.domain
now everything is customizable from section gmsh.domain
loadMesh() by default loads a hypercube domain and passes now all options from
loadMesh() and associated options
Merge branch 'develop' of https://github.com/feelpp/feelpp into feature/boundary
use new gmsh.domain section
set initial hsize in loadMesh
add _h and use _h
added rebuild option to gmsh section
added rebuild option to gmsh section
update laplacian.cfg to have a function in 2D which is non zero on the
boundary and not symmetric
added a cfg file for a test case on an ellipsoid domain
update emacs dirvars
Merge branch 'develop' into feature/boundary
rm
use MatZeroRowsColumns instead of MatZeroRows
Merge branch 'develop' of https://github.com/feelpp/feelpp into feature/boundary
update issue #155 changed handling of Dirichlet dof (elimination method)
 - changed interface to zeroRows 
 -  use MatZeroRowsColumns from PETSc for elimination (now the matrix is
 symmetric)

@vincentchabannes works only in sequential for now, need to adapt zeroRows()
in parallel (vectorPETScMPI)
update issue #155 simplify updateOnBoundary() 
it is now the same function for all dimensions
update issue #155
@vincentchabannes, @mszopos, @ranine :
 - zeroRows() works now in parallel and is simpler ( we could actually merge it
 with the sequetial version to avoid extra maintenance )
 - added support for clone() in VectorPetscMPI
 - changed FEELPP_ASSERT to CHECK or DCHECK
 - minor changes