Work on pdd, now it mostly works for the stationary case, also for higher order element. Just some small bugs :)

Implement element dof iterator class. May be used to iterate over all dofs of one element independent of dimension and degree of basis functions.

Bug Fix: The signed distance of corner-vertices of the implicit mesh is now calculated instead of set to a fixed value

added the -wsxm option

New Feature: Now deserialization works also for problems with different polynomial degrees in each component.