Bump major version, update history.
Added signature for changeset c4f53e99a024
Added tag v2.0.0 for changeset 120cbb7d7020
Test under Ruby 2.0 by default.
Inject support into Loggability directly, avoiding load order dependency
issues.
Bump version to v2.0.1.
Added signature for changeset bbf0ba1d6deb
Added tag v2.0.1 for changeset c25da00ba16e