Some minor changes were necessary so that we could change the ABI in
libsysprof-capture to be free from GLib (and therefore used by GLib).
This also adds some wrappers for capture API in libsysprof so that we
can continue to use GError from UI code.
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.
