BUG: issue #1690 starting to fix annotations in light box mode. Use the ...

...renderer from the light box proxy manager if it's defined

BUG: when in light box mode, switch to using 2d point handles for fiducials.

This works for placing new ones in limited testing, but not to convert existing ones
to 2d handles yet.

Issue #1690

BUG: switch fiducials between 2d and 3d as swap between light box and not.

TODO: initiate the change when the lightbox mode is changed, as opposed to when
move the fiducial in 3d.

issue #1690

BUG: update fiducial widgets on slice node changes.

If just update position, the handle widget 2d/3d type won't
get updated when switch in and out of light box mode.
This may slow things down a bit, but they'll be more correct.

Issue #1690

BUG: Avoid seed widget and representation having different renderers on creation.

Check the light box state so set the correct renderer on creation. Issue # 1690
Check that the seed representation has a valid renderer and active camera before
trying to set display position, should fix load crash with issue #2512

BUG: unify light box index calculation.

Try to use the volume slice spacing to determine the light box.
TBD: make sure taking the correct element of the spacing array.

Issue #1690

BUG: fix showing annotations in 0th light box.

This should fix the annotations showing up in the 0th light box when the annotation
should be in the -1th. Use floor rather than a cast to int to convert from floating
point display coordinate to light box index to avoid rounding toward 0.0 in negative
space.

Issue #1690

BUG: take into account volume spacing when deciding if should show a fiducial in a light box.
Calculate the distance between the fiducial and the slice at this light box index using distance from the fiducial point and the slice plane.

Issue #1690

BUG: try to get the point handles to show up when going into light box mode.

Delete and recreate seed widget when swapping in and out of light box mode, still work to do.

Issue #1690

STYLE: code clean up.

Change warnings to debugs, expand comments, fix a comparison to null.

Issue #1690

STYLE:  update comment on AddAnnotation to reflect implementation

Issue #1690

BUG: reset the glyph type when changing in and out of lightbox mode.

Needed to clear out the entry in the NodeGlyphTypes map so that the glyph would get updated on re-creation.

Issue #1690