#2300 Streamline the iterative solver setup and cleanup.  Change convergence criterion.

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21466 b5f69653-2bf5-0310-8201-b0dafb8e1405
#2441 - fix doxygen and coverage nightly tests

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21471 b5f69653-2bf5-0310-8201-b0dafb8e1405