This adds an undocumented "raw=1" query parameter to visualize raw
results without any averaging or filtering. Results are colored
according to the upload-part they came from.

Change-Id: I25590ace89dfe55380e28182c38aeb223e2e73b9
Reviewed-on: https://go-review.googlesource.com/37160
Run-TryBot: Quentin Smith <quentin@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>