Change subtitle of Image Op's result from muti-dim to image
This MR differentiates the results of Add Image Op and Add AuxGeom Op. Now the subtitle and title would show image. Meanwhile if auxGeom and image are both added, image would be a subset of AuxGeom since it's defined as a 2D auxGeom.
In Entity.h, flagSummary and flagSummaryHelper's signature now allows developer to pass in a string property if presented. This argument is meant to describe the entity type if bit vector is not enough.
Close #132 (closed)