adding convergence test
correcting the call of the function
fixing conflicts
Merge branch 'develop' of https://github.com/feelpp/feelpp into develop
Merge branch 'develop' of https://github.com/feelpp/feelpp into develop
Merge branch 'develop' of https://github.com/feelpp/feelpp into develop
Merge branch 'develop' of https://github.com/feelpp/feelpp into develop
add convergence test for stokes problem with Kovasnay exact solution
Merge branch 'develop' of https://github.com/feelpp/feelpp into develop