Merge branch 'develop' of https://github.com/feelpp/feelpp into develop
update issue #113
@asamake @dolleg I started implementing a nicer interface which would work
only if the points are in the mesh. It is not yet finished.
that allows to write:
```
u = vf::project( _space=Vh,_range=markedpoints(mesh,"toto"),_expr=cst(1.));
```
within u you retrieve the function u which is equal to 1 at the points marked 'toto'