Preparing Hydra 7.0.0 release

Removing 'hydra6' file (which was an alias to 'hydra' with a warning)
and pinning hydra to the latest versions. Adding wiki docs for 7.0.0
release. Cleaning up minor typos in release policy.
Merge pull request #52 from no-reply/feature/add-docs

Preparing Hydra 7.0.0 release

Merging in preparation for 7.0.0.rc1 and testing prior to Hydra Camp