Fix project bv curl conf

Hi,

Here's a new function to handle the Dirichlet boundary conditions for FE_Nedelec elements. It uses a fairly simple L2-projection method to compute the degrees of freedom on edges and faces. Rather than replace the current function, I've given it a new name as this may be less efficient on geometries with rectangular faces.

This also doesn't solve the issue when the face orientations are not of standard type.
This function seems to duplicate a lot of code that is already in the function above. This can be avoided by calling the hp function both for hp::DoFHandlers and ::DoFHandler. I know that you only copied the style that was there for the other function, so if you don't want to go through this I can understand, but it really would be much simpler if the function existed only once.