Add some comments for future reference.

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@23162 b5f69653-2bf5-0310-8201-b0dafb8e1405
Update Ubuntu package to require Xerces 3, since it is available on all supported Ubuntus (#2628).
Also swallow any error message in ubuntu.py if it isn't installed, to support legacy installations.

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@23163 b5f69653-2bf5-0310-8201-b0dafb8e1405
Fix weekly acceptance for minor accuracy change.

git-svn-id: https://chaste.cs.ox.ac.uk/svn/chaste/trunk@23164 b5f69653-2bf5-0310-8201-b0dafb8e1405