libcp1: revamp the interface

libcp1: revamp the interface

Narrow the oracle lookups to identifiers only, unifying symbols and tags,
and dropping labels.  Adjust the gdb client code, pending simplification.

Rename most entry points into a more consistent naming scheme.  Adjust
the gdb client code.

Bump the interface version.

Comment out support for default args for functions.

Drop support for strong using directives, introduce simpler interface
for inline namespaces.