We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
The flame graph view used to draw only so much of the graph that could
be displayed. Change to draw the whole graph, and add a scrollbar.
Does some tricks with the scrolling to keep the bottom of the graph
fixed when resizing or double-clicking, since it works better then.
