Correct mistake in doc `early_binding_for_speed.rst`

IPython notebook to Jupyter notebook in docs

This allows return types such as std::map<K, V>.

Fixes #1599

This fixes #1562

Add a comment about using setuptools and Cython together when passing Extension objects into cythonize() or distutils.
Resolves #338.

Encode relative path to working tree in code paths when possible.

Fix Python 2 and 3 have diffrent default encoding

Closes #1594.

- resolve string escapes  only outside of fstring expressions
- reject backslashes inside of fstring expressions
Also make some fstring errors non-fatal to keep parsing.

Allowed importing pyx files from ZIP archives

Issue a warning as this is a behavioural change that can lead to subtle code breakage of currently working code, in the same way that the previous behaviour could easily lead to bugs in general.

Resolves #1602.