Use POSIX "bswap16" to build on NetBSD/macppc.
done, proposed and requested by John D. Baker.
Update py-mongo to version 2.6.3.

Major package changes:
- added support for Python 3.x (N.B.: 3.2 or greater is required)
- pypi switched over to HTTPS - fetch using curl
- list the package in "databases" category as well
- homepage was moved - update
- cleanup comment a little bit
- the update fixes CVE-2013-2132

For changelist since pymongo 2.4.2 please visit
http://api.mongodb.org/python/current/changelog.html