Added support for the 'Restore' API call.
Added partial support for the 'Media' API call.
The 'protocol' parameter is not returning a streaming link.
Changed the name of the app folder access type parameter 'target' to 'root',
per the nomenclature convention used by the Dropbox API.
Added support for the 'Account Info' API call.
Added support for the 'Delta' API call. Minor update to the tests.
Added support for file upload with 'put_file', and file download with 'get_file'.
Added support for file operations: 'copy', 'move', 'delete', 'undelete', ...
Simplified the process of nonce generation to eliminate an external dependency.