Rev the version number of the oauth-credentials plugin.

Pull in the new 1.10 release of the core Credentials plugin to get the DomainRestrictedCredentials

Implement a new OAuth2Token interface that combines OAuth2Credentials with DomainRestrictedCredentials, which allows us to limit the applicability of a token credential to only the contexts where it provides sufficient oauth scopes to authorize API interactions.

For instance, we may store an OAuth2 refresh token that provides access to a user's GMail, Google+, Google Drive, and nothing more.  We wouldn't want this credential to show up in plugins that interact with Google Calendar, but we would want them to show up in plugins that interact with Google Drive.

Moreover the "getAccessToken(OAuth2ScopeRequirement)" API allows us to still limit this tri-scoped token down to just the scopes the consumer requires (assuming we perform a refresh token => access token exchange), if we so choose.
switch to SNAPSHOT versioning to appease the mvn release plugin