Fix crash, convert back to PyObject pointers.

There was some weird memory corruption caused by how pepy_parsed_init()
was parsing arguments. The result was that accessing attributes or methods
which didn't exist would periodically cause segfaults. This code was leftover
from an earlier way of doing things and doesn't need to be done this way.
Just parse straight to a C style string instead of this crap.

Also implement support for signature, machine support.

Also, add Py_TPFLAGS_BASETYPE as you should.