Made the print python 3 style. pep8 and link to memoryviews.

Updated cythonize.

Put the pip installation first.

Improvements of the docs.

Split prototype part off a utility function to move the actual implementation to the end of the C file.

Misc typos

Found via `codespell`

Closes #1606.

Mention Typed Memoryviews in the Working with NumPy doc.

Updated the example for --annotate.

Increase the ccache size on travis from 100M to 150M as we've probably passed the limit already with all the tests that we have now.

Do not issue "redefined" warnings on C++ function overrides with different signatures (previously only applied to methods).
Closes #2013.

Actually show "redefined" warnings, but only for "cdef extern" blocks, i.e. the exact case described in #1874.
Closes #1874.

Silence "redefined" warning again as it is more annoying than helpful to receive it for every pxd-defined cpdef function.
See #1874.
Closes #2013.

Repair the coercion of C string literals to C++ strings for function arguments: must create a copy for non-const arguments and can use C++ coercion for const literals.
Closes #2132.

Use pre-5.0 Tornado version as Jupyter dependency in Py3.3 since Tornado 5.0 dropped support for it.