Uses default value formatter (%v) as a last resort fallback
Expose ExceptionLogReporter.Logger
delegate grohl.ReportException to DefaultLogger
hey race detector found nothing
add a logger that goes through a channel.

should make grohl logging behave better in multi-goroutine environments.

/cc @alindeman @asenchi if you're curious :)
huge grohl rewrite

* separate Context into a separate type from the Logger
* support the Statter and ExceptionReporter interfaces
* Remove mutex concerns, add channel logger
put format tests in format_test
actually add format test
move some function declarations around
allow you to set a custom ExceptionReporter on a context
Merge pull request #3 from alindeman/formatter-fallback

Uses default value formatter (%v) as a last resort fallback
merge #3
Merge pull request #4 from technoweenie/rewrite

huge grohl rewrite