ENH: over ride annotation nodes with markups nodes

When reading in a mrml file that has annotation fiducial
nodes, point display nodes, or control point storage nodes,
use the corresponding markup nodes that have been registered
with those node tags:
AnnotationFiducials -> MarkupsFiducial
AnnotationPointDisplay -> MarkupsDisplay
AnnotationControlPointsStorage -> MarkupsFiducialStorage

Parse the extra xml values and set markups values. This will result
in one markups fiducial node per annotation fiducial in the mrml file,
hierarchies are ignored. The text display node is also ignored,
the resulting fiducial will have the text be the same color
as the annotation fiducial glyph/point.