This uses an augmented red-black tree to create an interval tree with
non-interval lookups. That amounts to storing address ranges within the
red-black tree, but looking up by single address.
This also indexes the first position of a file by filename so that we can
skip items in the capture file. Generally, embedded files are a single
frame so that will only be one frame to look at. But even when it is a
few frames, they are generally sequential so this vastly reduces how many
frames we'll need to look at for files.
The goal here is to break up libsysprof into a library for recording
profiles (using libsysprof-capture) and a library for analyzing profiles
(both used by the sysprof UI).
