support for wide python builds for unicode chars >= 0x10000

By default python 2.7 is a narrow build, which means it only supports unicode codepoints < 0x10000.
You can test yours by trying
```python
>>> uc = unichr(0x10000)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: unichr() arg not in range(0x10000) (narrow Python build)
```
With this patch and (re)installing with `brew install python --with-wide-unicode` the above won't fail anymore:
```python
>>> >>> uc = unichr(0x10000)
>>> uc
u'\U00010000'
```