This comprises a massive rewrite of the UI for browsing captures. We use
the SysprofAid class to scan capture files for content and then auto-
matically add visualizers and details pages.
To avoid breaking things incrementally, we just land this as a very large
commit. Not necessarily ideal, but given the amount of stuff that could
break, this is easier.
As part of this process, we're removing a lot of the surface API so that
we can limit how much we need to maintain in terms of ABI.
This ensures that we only calculate averages for marks that have a valid
duration. We also need a new field for the number of averages we added
so that we don't skew the results.
