- empty string as marker for failure to discover calling function
- tighten up logger usage - don't rely on std logger internally
Also fix ordering of expected/got in logrus_test.go to ensure correct
output form test failures.
If log.SetReportMethod(true) then method=PACKAGE.FUNCTION will be added
as a field to log lines.
eg: time="2016-11-25T19:04:43-08:00" level=info method=main msg="log
testing"
TODO: documentation, examples