add support for classification rate

this adds a bit to the end of the report for the classification
rate that we currently have, as well as the jobs with the most
still unclassified errors.

Change-Id: Ia1426bef2d788f8b2c14e5a1402a5ac01a3561f7
add per job percentages for responsibility of fails

this provides per build_name failure percentages. This shows
what percentage of the failures of a build_name a bug is
responsible for.

Change-Id: I77f7997331342f244a53a4f98198da8f8145814f
Merge "add support for classification rate"
Merge "add per job percentages for responsibility of fails"