[functionals.ls] some clean up
[operators.elliptic-cg] kepp refs dependent objects need
[localevaluation.swipdg] white space
[space.dg] added DiscontinuousLagrangeProvider
[functionals.swipdg] added first draft of DirichletBoundarySWIPDG
[operators.elliptic-swipdg] added first draft