Add PdroidManager to getSettings package name check.

Since this hadn't been added before, I am unsure of the exact consequences of its previous absence. But it
seems better to be safe than sorry.
Add Sms.Intents class and move intent constants inside

Mainly useful at this point as an easy method of including some documentation. Wsot pulled these intents
into constants and CD decided to put them into a class. Echoed here.