remove references to Storage

Remove all references to the non-implemented, non-working Storage module
per request of the OA.
Merge pull request #136 from dyoung522/fix/remove-storage

remove references to Storage
CAP: expect NAK, not NACK
bump version to 2.0.8
Merge branch 'maint'

Conflicts:
	examples/plugins/memo.rb
	lib/cinch/storage/yaml.rb