Integrating sentinel into samoa

Hi, I'm Amir Rahnama (@ambodi).

as I discussed this with Gianmarco De Francisci Morales (@gdfm), in this pull request we want to integrate Sentinel (https://github.com/ambodi/sentinel) into SAMOA. Also add more components to it and make it complete.


We cannot include moa as a dependency as it is GPL, thus incompatible with ASL.