Xfem

bug fix release (webgui, DrawDC) [consistent to ngsolve v6.2.2303]

minor adaptations and cleanups (compatible to NGSolve v6.2.2303)

New feature:

Aggregated FEM (Badia et al.)

basically bug fixes
and new feature combinations (e.g. DG + spacetime in 1D,2D,3D)
and preliminary sphinx docu

This release is compatible with v6.2.2204 of NGSolve.

compatible to ngsolve v.6.2.2104 and includes the joss publication.

joss