This will look at what was in the reader before and create a new local
profiler from that. This still needs to add support for restoring info
from sources which need to be inflated.
This gets added as a metadata chunk to the capture file so that we can
use it later to recreate the session. The goal is to add something like
ctrl+r to run the capture again with identical settings to the previous
capture.
As we gain in usage, we need to be more careful about using a prefix
that will not collide with other symbols. So version 3 of our ABI will
change to using Sysprof/SYSPROF/sysprof as the various prefixes.
The soname/api version bump will happen later on this branch so that
things are easier to test up until then.
