#2340 Make `Node` use `NodeAttributes` to store its attributes.

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@18075 b5f69653-2bf5-0310-8201-b0dafb8e1405
whitespace edit to see if I have fixed password issue

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@18076 b5f69653-2bf5-0310-8201-b0dafb8e1405