Move UI data in LogCatFilter to a separate class

There were a couple of pieces of UI data (unread count & flag
indicating whether a filter is transient) associated with a filter.
This CL moves both of them out into a separate class. The panel
maintains a mapping from a filter to its associated UI data.

The core filter class has been moved out into ddmlib.

Change-Id: I325176c33094d583c0ef9abe890e5462aeeb4945
8 files changed