Updated email hash to Gravatar specifications

Gravatar email hashes have two requirements:
* Whitespace must be trimmed
* Email should be downcased
Merge pull request #21 from 5thWall/gravatar_hash

Updated email hash to Gravatar specifications
fix onebox for your own site
Merge branch 'master' of github.com:discourse/discourse
Working out outdated migrations

Several migrations were failing when running db:migrate at the initial release version from an empty database.
These changes took out statements that were causing migrations to fail, usually because of references to models that no longer exist.
Merge pull request #11 from keekerdc/fixing-outdated-migrations

Working out outdated migrations