- The declaration have to be the reverse of C++
  as the iterator class matches both iterator and const_iterator classes

- bucket API
- load_factor API
- erase and insert with begin/end iterators

- bucket API
- load_factor API
- erase and insert with begin/end iterators

Avoid uninitialised C variable (and thus potentially undefined behaviour), even if it's not actually being used in that case.

Improve libcpp.unordered_map API

Add zip_safe=False to userguide setup.py

Misc. typos

Closes #2194.

Closes #2193.

This adds notes in the documentation to include zip_safe=False when
using setuptools instead of distutils for setup.py.

Because cimport will not load pxd definitions from a zipped egg file and
the default format when installing from a source package using
setuptools and "python setup.py install" is to create a zipped egg,
including this option will guard against this error when people install
this way.

Found via `codespell -q 3`

Closes #2134.

Added %%cython options.

Patch to add front() and back(), as per issue #2123.

Copy also the short long_neg() code from CPython for the specialised "abs(PyLong)" implementation to avoid jumping through call pointer indirections.

Added argument list for pyximport.