Allow topic separator to be redefined and fix publish calls for py3

Merge pull request #88 from smira/mplv2

chore: relicense under MPLv2

Merge pull request #83 from smira/release-0.8.2

Bump version to 0.8.2

Merge pull request #81 from smira/release-0.8.1

Bump version for 0.8.1 release

Merge pull request #74 from smira/release-080

Bump version, Python 3.x support should be mature enough.

Version bump 0.7.4.

Version 0.7.3.

0.7.2: fix missing VERSION file.

txZMQ 0.7.1: preliminary support for Python3.

txZMQ 0.7.0 with support for pyzmq >= 13.