There are several obsolete items still in the repository, such as graphics for old arjuna product logos, xerces (obsolete now the JDK has xml support), and assorted classes that should no longer be used (e.g. licence utils even though we don't have licence keys any more, concurrency utils now found in the JDK). Remove this cruft from trunk.

Whilst we are at it, retrofit the exceptions to have constructors that take Throwable arg (not available in JDK Exception when the code was written), then update their usage to take advantage of it. Remove unused methods that were previously deprecated and deprecate anything currently unused that looks like a waste of space.