Use a different hack to get CC name.

Get the name of the C compiler by hacking into the innards of distutils
and accessing a non-public var, albeit one which hasn't moved in many
years.  This is slightly less awful than extracting a name from
sysconfig.
Add setup.py command to build .y parsers.

Use lemon to build parsers.  Refactor accumulation of source file names.
Add Python C binding for CFCHierarchy.
Prepend host-dependent members onto Obj.

Prepend a a host-dependent macro, `CFISH_OBJ_HEAD`, onto object struct
definitions.  For now the macro is a dummy for all hosts.
Move refcount/host-object into host-specific code.

Move the cfish_ref_t union member variable into the CFISH_OBJ_HEAD macro
and out of the definition for Obj, since refcounting and host object
caching will vary per host.  As a consequence, the `vtable` member is no
longer at the top of the object, requiring a few changes to places in
the code which expected to find it there.