2505 created T2SwapWriter, added GetNumAllCells method and also some comments in the force laws...

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21427 b5f69653-2bf5-0310-8201-b0dafb8e1405
#2441 - add `mVtkCellDataName` and `GetDataForVtkOutput()` to `AbstractCellWriter` (the latter is overridden in all subclasses) and beef up cell writer tests

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21429 b5f69653-2bf5-0310-8201-b0dafb8e1405
#2441 - doh

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21430 b5f69653-2bf5-0310-8201-b0dafb8e1405
#2505 - Doh in a German accent

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21432 b5f69653-2bf5-0310-8201-b0dafb8e1405
#2486 Try again

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21439 b5f69653-2bf5-0310-8201-b0dafb8e1405
Make it easier to diagnose which model is failing in `TestPyCmlLong`.

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@21441 b5f69653-2bf5-0310-8201-b0dafb8e1405