Partial implementation of WB-499 Should Volume ID Place a Symbol:...

Partial implementation of WB-499 Should Volume ID Place a Symbol: Identification symbols for volume identification have been added but some issues remain including (1) should a node (voxel) identification also identify the corresponding voxel (node); (2) Should Identify Window Clear button remove only text but leave symbols, and (3) Should RID remove symbols but leave text.