Add real, user, and sys times to BAYESTAR log messages

When the bayestar-localize-coincs or bayestar-localize-lvalert scripts are called with --loglevel=info or higher, they will now output additional runtime measurements. Specifically, they will output the "real" time (wall clock time), "user" time (total time spent in userland across all threads), and "sys" time (total time spent in kernel land across all threads), similar to the UNIX time(1) tool. Here is an example of the formatting:

2020-05-12 18:57:12,024 INFO finished computationally-intensive section in real=0.918s, user=36.339s, sys=0.293s