Create an empty string with the new Unicode API.

And PyObject_Str() and PyObject_Repr() don't make strings ready in debug
mode to ensure that the caller makes the string ready before using it.

Still lacks docs for Windows (anyone?).

Still lacks docs for Windows (anyone?).

Also, add tests for these methods.

And use surrogates macros everywhere in unicodeobject.c

This fixes a regression compared to 2.x, where sys.modules.items()
returns a copy, as indicated by a comment in the source.  Diagnosis and
patch by Erik Tollerud.

It was already the case with Python 2.  However, the corresponding
sys module entries are now set to None (instead of an unusable file object).

It was already the case with Python 2.  However, the corresponding
sys module entries are now set to None (instead of an unusable file object).

Initial patch by Sjoerd de Vries.

Initial patch by Sjoerd de Vries.