Binary compatibility
We will not worry about maintaining binary compatibility with the
client APIs between different versions of BloCxx, since it is trivial
to solve the problem by installing 2 or more different versions of the
client libraries. This is just an issue for package developers to
provide some way for multiple versions of the client libraries to be
installed simultaneously. Note that we do try hard to maintain
source compatibility for client applications, if at all possible we
mark interfaces as deprecated when a replacement has been created. They
are deprecated for at least one release and then removed after client
applications have had a chance to migrate.