Object graph visualizer - temporarily disable
collection support to make porting the code
to new NRefactory more feasible.
Object graph visualizer - use Strings instead
of Expressions to refer to members.
The main purpose of having a String representation
of members is persisting expand state between
debugger steps.
Debugger visualizers - switch from DebugType to
IType in declarations - the easy part.

The next part is to port method implementations.
Use OfType<T>()
Use KnownTypeCode.
Adapt to removed WPF helpers.
OnPropertyChanged() thanks to [CallerMemberName].
Incorporate some feedback.
Debugger visualizers - progress towards getting the project to compile.
Debugger visualizers - merge a few small helper
files. Rename Graph -> GraphVisualizer.
Formatting.
Debugger visualizers - GetFieldsAndNonIndexedProperties.
Debugger visualizers - progress (Grid visualizer remaining).
Merge branch 'newNR' into newNRvisualizers
Make debugger visualizers compile.
Re-enable debugger visualizers in debugger
tooltips. Object graph visualizer crashes,
collection and text visualizer seeem to be
working.
Next up is to make object graph vis work.
Object graph visualizer starting to work.
Object graph visualizer - note possible bug.
Merge branch 'newNR' into newNRvisualizers
Re-obtain hash code method after debuggee is restarted.