Implement embed_py_func_global().

Pulled similar code out of git history.
Check that passing literals to embedded functions is ok.
First stab at embed_py_meth().

Not tested much. Many more tests to come.
Check that passing args from PHP to Python is as expected.

I.e. pass by assignment.
Add a test to check that references pass through methods correctly.
Merge branch 'pypy_bridge' into pypy_bridge_func_meth_rethink

Conflicts:
	testing/test_pypy_bridge_arg_passing.py
We should not rely upon returning when testing pass by ref.
Ensure that embedded Python methods when called are pass by ref.
Revises tests for passing in existing PHP refs to Python.

And remove a pdb.
Use hippy's internal method table for Python methods.

This means methods must be embedded directly after class definition. We
will need to put braces around class defs to prevent all classes from
being compiled first.

This may be reverted.
Revise and add tests for more method stuff.
Only look in parent PHP scope if one exists.
Fix test and give explanation.
is None, not == None. Also dict.get needs a default in RPython.
Add scope to embedded Python methods.
Allow embed_py_meth() to overide a method from a superclass.
When embedding a constructor, populate the constructor attribute.

The constructor is given it's own attribute in the class, presumably for
fast lookup. Without this, embedded Python constructors will not be
called when the PHP class is instantiated!
Add a getattr test.
Revert php->py calling to pass by value and wrap whatever we are given (instead of always a reference).
Add a test for a possibly incorrect behaviour.