ObjectManifestMetadataKey value should be lower case.

The API returns the value in lowercase

Dictionary.ContainsKey(CloudFilesProvider.ObjectManifestMetadataKey) always returns false due to case sensitivity
Merge pull request #3 from jonwalton/master

Fixes case sensitivity with CloudFilesProvider.ObjectManifestMetadataKey
Fixed an issue with the Cloud Files Provider's Copy object
Fixed merge conflicts
Merge pull request #4 from alanquillin/FixCopyObjectWithCOPYHTTPVerb

Fixed an issue with the Cloud Files Provider's Copy object
Merge remote-tracking branch 'rackspace/master'