tthsum source and windows binary

tthsum-1.3.1.tar.bz2 (md5 59d8a333ad607d6d1d1c830c8651ca50)
tthsum-1.3.1.tar.gz (md5 b641a7cfc932a9515d33d10dfb60f5ff)
tthsum-1.2.0-win32-bin.zip (md5 a8c756a3ae93732d93380fb383754dce)

See changes in the changelog.

Latest is 1.3.1. But for x86 systems (little endian and misalignment safe), there is no noticable difference between 1.2.0. That means that the windows users can safely use the 1.2.0 version.