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.

Closes #2124.

Inline toggleDiv

Fix duplicate declaration in posix/time.pxd

Closes #2127.

Closes #2128.

Re-enable "auto late includes" based on a preliminary directive. We have the feature, so allowing its use won't hurt, as long as users are aware that they will have to change their code later.
See #2079.

Work around BPO-32973: CPython 3 can rerun the module PyInit function if the extension module is re-imported under a different name.
https://bugs.python.org/issue32973

Inlined the toggleDiv function to workaround that jupyterlab doesn't support script tags in html.