Rationalise base and geerdes classes, constructors and methods. Ignore-this: d9d4d88566a6d110844d91d4c70513cd Towards a more standardised interface. Some of these changes (generalised constructors and reader functions) are necessary for amuse-database-admin functionality and some other CHARM-like things. darcs-hash:20090716154406-16a00-8a9b4fb1fc1f5ba75af66a1bbd87e1bb68e02493.gz committer: Jamie Forth <j.forth@gold.ac.uk>