Munkres

- Switched from Nose to Pytest for testing. Patch courtesy kmosiejczuk,
[PR 32](https://github.com/bmc/munkres/pull/32), with some additional
cleanup by me.
- Fix to [Issue 34](https://github.com/bmc/munkres/issues/34), in which
`print_matrix` wasn't handling non-integral values. Patch courtesy finn0,
via [PR 35](https://github.com/bmc/munkres/pull/35).
- Various changes from `http:` URLs to `https:` URLs, courtesy finn0
via [PR 36](https://github.com/bmc/munkres/pull/36/).

- Removed `NoReturn` type annotations, to allow compatibility with Python 3.5
releases prior to 3.5.4. Thanks to jackwilsdon for catching that issue.

- Version bump to get past a PyPI publishing issue. (Can't republish
partially published 1.1.0.)

- Only supports Python 3.5 or better, from this version forward (since Python
2 is at end of life in 11 months).
- Added `typing` type hints.
- Updated docs to use `pdoc`, since `epydoc` is pretty much dead.

- Merged [Pull Request 11](https://github.com/bmc/munkres/pull/11), from
[brunokim](https://github.com/brunokim), which simplifies conversion of a
profit matrix to a cost matrix, in the default case.

- Merged [Pull Request 7](https://github.com/bmc/munkres/pull/7), from
[mdxs](https://github.com/mdxs), which fixes a message.

- Added more tests.

- Docs are now generated with [pdoc](https://github.com/BurntSushi/pdoc).

- Merged [Pull Request 24](https://github.com/bmc/munkres/pull/24), from
[czlee](https://github.com/czlee):
- Change to step 4: When it looks for a uncovered zero, rather than starting
at row 0, column 0, it starts where it left off, i.e. at the last
uncovered zero it found. Since it doesn't start at (0,0), when it gets to
the last column it now loops around to the first, and exits unsuccessfully
if it got back to where it started. This change reduces this reduces the
solving time for (certain) large matrices. For instance, in tests,
solving a matrix of size 394×394 goes from about 2 minutes to about 4
seconds.
- Since Python 3 started cracking down on unnatural comparisons, the
`DISALLOWED` constant added in
[Pull Request 19](https://github.com/bmc/munkres/issues/19) no longer
works. (It raises a TypeError for unorderable types, as is expected in
Python 3.) Since this constant is meant to act like infinity, this
modification just changes the two lines where it would otherwise try to
make an illegal (in Python 3) comparison between a number and
`DISALLOWED_OBJ()` and gets it to behave as if `DISALLOWED` is always
larger.

- Added Travis CI integration.

- Added some unit tests. See `tests` and `tests/README.md`.