Rare Buffer Overflow Fix

Fix buffer overflow in sprintf call in combine.c. This only occurred if the system failed to provide as many threads as the user requests.

Python 3 Support

Do not use this version: there is a rare potential buffer overflow bug.

Reports of Python 3's death have been greatly exaggerated (to my mild disappointment). This library now supports both Python 2 and Python 3.

Tiny Fixes

Do not use this version: there is a rare potential buffer overflow bug.

Fixed memory leak in documentation example and got rid of explicit request for clang 4.0 in Makefile.

Initial release

Do not use this version: there is a rare potential buffer overflow bug.