Updated package.json file.
Added stream get/set with proper error and callback support.

Signed-off-by: marco.minetti <marco.minetti@novetica.org>
Reworked get/set implementations with proper error and callback support.
Added cache got implementations.
Updated documentation in cache.server.js.

Signed-off-by: marco.minetti <marco.minetti@novetica.org>