Total redesign. Breaking changes.
year bump
Changed name to rogu (Japanese for Log). LogErrf can now handle a nil error. Misc. improvements and testing.
Updated README.md to reflect name change to rogu.
Removed prefix from default loggers.
Update README.md
Simultaneously log to multiple writers; handle panics; more tests.
Changed how Rogu handles concurrency.
Merge branch 'release/0.2.0'

Conflicts:
	README.md