Munkres

- Updated `setup.py` to produce a wheel.

- Fixed URL to original implementation. Addresses
[Issue 4](https://github.com/bmc/munkres/issues/4).
- Fixes from [kylemcdonald](https://github.com/kylemcdonald):
- `print_matrix()` no longer crashes on 0. Fixes
[Issue 1](https://github.com/bmc/munkres/issues/4).
- Fixed bug where step 3 could quit early. Fixes
[Issue 16](https://github.com/bmc/munkres/issues/16).
- Added step 2 break for a small optimization.
- Added time bound to README. Addresses
[Issue 15](https://github.com/bmc/munkres/issues/15).
- Versioning will now adhere to
[semantic version specification](https://semver.org).

- License is now ASL.

Fix from Stephan Porz (s.porz /at/ uni-bonn.de):
- Fix pad_matrix: pad_value now actually used

Fixes from Markus Padourek (markus.padourek /at/ gmail.com):
- sys.maxsize fix and bump to 1.0.6
- Updated to Python 3.x

- Fixed documentation of print_matrix() in module docs.