Releases for Drupal 8 Cache Backport

This is the first stable release of D8Cache, the Drupal 7 backport of large parts of the Drupal 8 caching system.

This is the first release candidate for d8cache.

There are still open bugs and documentation fixes that will go in before a stable version is released.

However for all purposes this is stable and tested enough now to warrant being a release candidate.

First alpha release of D8Cache with full support for cache tags and cache max-age.