Debugging support

[favonia]

Based on some private conversation, I believe what we want is some support for developers to debug. @mmcqd

The current design is to make users happy, but we may also want to support spewing out more debugging information.

[favonia]

@mmcqd @TOTBWF @jonsterling I have two competing designs:

1. Have a separate Logger and Reporter can use Logger directly.
2. Only add those functions to Reporter.

I wonder if you have any Insights... how would you like to add the ability to give more debugging information?