Creating of classes (types) and instances is much more like CPython now.
You can use "type('name', (), {...})" to create classes.

Added 0 to the list of primes. Funky primes, these.

import works for simple cases.  Still work to do on finding the right
script, and setting globals/locals correctly when running an imported
function.

A big change.  Micro Python objects are allocated as individual structs
with the first element being a pointer to the type information (which
is itself an object).  This scheme follows CPython.  Much more flexible,
not necessarily slower, uses same heap memory, and can allocate objects
statically.

Also change name prefix, from py_ to mp_ (mp for Micro Python).