enhancement: post-filtering of functions

[percontation]

1. Ability to mark certain functions as hidden, temporarily collapsing them and all their sub functions out of the trace as if they were filtered.
2. Ability to focus on a specific instance of a specific function call, filtering out everything before and after that function. Maybe more like zooming in / locking the qira view on to it temporarily. Would be easier to not get lost, and depending on the implementation might help perf.

I'm working on a statically compiled binary right now, but such things should be useful for ordinary large binaries. These things would go great with some kind of dynamic call trace view.

[geohot]

I'm very supportive of this. Filtering is a somewhat hard problem to make fast, and will add complexity to the qiradb, but I think it's worth it. Shard the qiradb!

So I have arrow keys to jump between function start and ends. But yea, when collapsed it would make a nice call trace view.