py visualization

git-svn-id: http://svn.code.sf.net/p/netgen-mesher/code/netgen@871 38e36fca-e102-11dd-b6c5-65a6809f2f0c
ngs needs dummy clearsolutiondata

git-svn-id: http://svn.code.sf.net/p/netgen-mesher/code/netgen@872 38e36fca-e102-11dd-b6c5-65a6809f2f0c