Windows Event Log, error output

Adding more Event Log support, and modifying the loggers so they return
errors in their operational functions.

logging/TODO

@@ -2,10 +2,9 @@
   https://stackoverflow.com/a/24809646
   https://golang.org/pkg/runtime/#Caller
 
-- Support simultaneous writing to multiple Loggers.
-
 - Suport remote loggers? (eventlog, syslog, systemd)
 
 - DOCS.
+-- Done, but flesh out.
 
 - Unit/Integration tests.