The return from git shortlog -s apparently lacked a final \n which
caused the string matching for authors to omit the last listed author.
Fixed by using '^' and '$' tokens and string matching in multiline mode.

Also fix escape sequences deprecated in Python 3.6.

[ci skip]

- Add ability to get pull request number from Homu auto merges.
- Print number of merged pull requests.

[ci skip]

When python is invoked with switch -3, it emits waring "classic int division"
for strict integer divisions. The same behavior is now implemented to numpy
with this fix

With USE_DEBUG=1, the wrong python was being used
to create the virtualenv, meaning that installed
packages (e.g. Cython) were being installed to
the wrong location.

Currently when the squash-merge button is hit on github, the PR title
with "(#PR)" appended is used as the commit message summary line when
the merge is fast-forwarded. This PR adds the ability to pick out the
corresponding PR numbers from the git log output.

Note that github may change this in the future and one early squash
merge in the 1.12.0 release did not have the PR number appended.

ENH: Add a tool for release authors and PRs.

Add the script tools/announce.py to generate the author and pull request
lists needed in release announcements. Some bits of this are taken from
the scipy gh_list.py and authors.py tools.

Usage:

$ ./tools/announce.py <github_user> <github_password> <revision_range>

The output is utf8 rst.

[ci skip]

Copy tempita from https://github.com/gjhiggins/tempita with a few
changes to remove the six dependency.  This removes a dependency on
Cython's tempita, which is not to be relied on as it is considered by
the Cython folks to be an implementation detail. The package is named
npy_tempita so that it can always be distinguished from an installed
tempita.

The cythonize.py script is changed to use the vendorized tempita.

Refactors the randint helpers to use a Tempita
template. This will reduce technical debt in the
long run.