tidying

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21006 b5f69653-2bf5-0310-8201-b0dafb8e1405
#2488 - try fixing Intel build

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21008 b5f69653-2bf5-0310-8201-b0dafb8e1405
#2441 - improve comments in tutorials

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21009 b5f69653-2bf5-0310-8201-b0dafb8e1405