Renamed VirtualListViewSelection to DisplayListSelection, because
it's now tied to the DisplayList implementation. Hooked it up to
handle SelectionChanged events.
Also, tweaked the code list item style to remove the one-pixel gap
between items. Somehow I manage to click on the dead zone with
surprising regularity.
The disassembled lines are now shown in the custom-styled list view.
The DisplayList isn't being kept up to date on edits, but since we
can't edit anything yet that's not too limiting.
Pulled more code over, including the mostly-GUI-agnostic bits of the
source generation and assembler execution code.
