Simple discovery of memory counters to display in the capture set. We will
want to refactor this type of stuff in the future into recording "gadgets"
that combine a data-collector with a visualization layer.
The goal here is to avoid having to hard code what visualizers are shown
from the .ui files. We just should add things that we find are supported.
Long term, I think we'll add a concept of an "instrument" which is the
combination of a data source (SpSource) and a visualizer (SpVisualizerRow).
The other goal here is to enable the future support for discovering marks
and adding rows for each of those threads.
The lib/ directory was getting a bit out of hand, so this tries
to organize things a bit so it is easier going forward to locate
the code people want to patch.
