[la.container.affine] add convenience register_...() methods
* those forward all arguments to the container constructors
[parameters.functional] update exception
* use stuff instead of pymor exception
* update information, especially include the expression which is most
  important for debugging
[functions.default] fixed stupidly wrong register_...() methods
[functions.default] minor update, white space and reordering
[functions.interfaces]
* names and static_ids start with pymor instead of dune.pymor