#2569 Tidy and focus the tutorial

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@22709 b5f69653-2bf5-0310-8201-b0dafb8e1405
#2569 Tidy and focus the tutorial

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@22710 b5f69653-2bf5-0310-8201-b0dafb8e1405
New trac has slightly different wiki rules, escape some words.

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@22711 b5f69653-2bf5-0310-8201-b0dafb8e1405