* Test bytes_per_second and items_per_second.
* Test SetLabel.
* Reformat.
* Make State::error_occurred_ private.
* Fix tests with floats.
* Merge private blocks
* refactor
* Move default substitutions into library
* Move default substitutions to the *right* place in the library
* Fix init order issues that caused test failures
* improve diagnostics
* add missing include
* general cleanup
* Address review comments