Increment version to v1.0.8: Support overwrite upload parameter. Support specifying face coordinates in upload API. Support specifying context (currently alt and caption) in upload API and returning context in API.Support specifying allowed image formats in upload API.Support listing resources in admin API by multiple public IDs. Send User-Agent header with client library version in API request. Support for signed-URLs to override restricted dynamic URLs.  Move helper methods and preloaded file to separate file and fix Composer autoload. Minor fixes.