Properly match process kill/death/leave messages for secondary processes

Summary: The regexes for process exits were no matching secondary processes, which makes it understandably hard to track their
lifecycles. Fix it by including ':' in the process name match groups, as in the process start regex.

Test Plan: Run, match the chrome process name, com.android.chrome, see its secondary processes start reporting their death.
Merge pull request #53 from LouisBVL/parse_proc_death

Properly match process kill/death/leave messages for secondary processes