[Pharo-project] Some code

Stef, I tried to push this to the inbox, but there was a problem, and "the administrator has been notified." Oh well. Attachments work. Attached are my FFI extensions, including non-aligned (with which I have been able to slide so far???) double arrays, catalog (schema) information for ODBC, value adapters, and some patching around weak collections to make a thread safe and self-cleaning sort of them - essential IMHO. None of this is particularly polished. Some parts are more heavily tested than others. Bill