Currently there is no symbol for Fatal-level log entries, so they appear
with "-2", which is distracting.
This patch makes the Fatal log entries have their own symbol, ☠.
glog works fine and has great features, but it does not play along well
with systemd or standard log rotators (as it does the rotation itself).
So this patch replaces glog with a new logging module "log", which by
default logs to stderr, in a systemd-friendly manner.
Logging to files or syslog is still supported.
