Remove explicit flush calls since line_buffering is enabled.
archive checkpoint: Reset timer after the checkpoint has been committed
check: Fix a check --repair issue and added more tests
Attempt to make the archive metadata resync more robust
Preparing release
Move website to attic-backup.org
website: github ribbon should be a https link
tox: Make sure mock is installed in the py32 env
crypto: convert attic.crypto into a cython module

This will give a slight performance boost and make the openssl
detection/linking more robust.
docs: Add link to Slackware packages
cache: Speed up cache rebuild by caching archive metadata requests