Add more options to `am monitor` to make it easy to automate

-s: Simple output, only print one line summary for each event
-c: Always assume the input is [c]ontinue
-p TARGET: Only print events from a given process / package

Bug: N/A
Test: manual test
Change-Id: Icf6f01d85a396cccb211c29bd070c9d0fa8b71b9