Changing how debuggerd filters log messages to different locations.

The system by which debuggerd filters its output to different locations
is now based on an enum called logtype with easy to understand
categories for log messages (like THREAD, MEMORY, etc.) instead of the
old, fairly esoteric scope_flags variable.  Now much of the output that
previously went to logcat does not show up on the screen, but all output
can be found in the tombstone file.  In addition, the tombstone's
location is now printed so it can be located easily.

Bug: 15341747
Change-Id: Ia2f2051d1dfdea934d0e6ed220f24345e35ba6a2