The first argument to the type.make_new method is naturally a uPy type,
and all uses of this argument cast it directly to a pointer to a type
structure. So it makes sense to just have it a pointer to a type from
the very beginning (and a const pointer at that). This patch makes
such a change, and removes all unnecessary casting to/from mp_obj_t.
This patch overhauls the network driver interface. A generic NIC must
provide a set of C-level functions to implement low-level socket control
(eg socket, bind, connect, send, recv). Doing this, the network and
usocket modules can then use such a NIC to implement proper socket
control at the Python level.
This patch also updates the CC3K and WIZNET5K drivers to conform to the
new interface, and fixes some bugs in the drivers. They now work
reasonably well.