with the following properties:

- writes XML VTK files
- no additional libraries required
- unstructured leaf grid
- point and cell data (i.e. P0 and P1)
- works in parallel (yes you can visualize data computed in parallel !)

Use ParaView 2.4 to display these files.

To do:

- binary output (using base64 encoding)
- name and directory management (parallel, time-dependent produces lots of files)
- nonconforming output for DG
- P2 function output
- testing of vector output (is already implemented)

[[Imported from SVN: r3771]]