- Implement code line/func/etc. (only for debug?):
  https://stackoverflow.com/a/24809646
  https://golang.org/pkg/runtime/#Caller
  -- log.LlongFile and log.Lshortfile flags don't currently work properly for StdLogger/FileLogger; they refer to the file in logging package rather than the caller.

- StdLogger2; where stdout and stderr are both logged to depending on severity level.
  - make configurable via OR bitmask

- Suport remote loggers? (eventlog, syslog, systemd)

- JSON logger? YAML logger? XML logger?

- DOCS.
-- Done, but flesh out.

- Implement io.Writer interfaces