0030690: Draw Harness - provide XDisplay command for displaying XDE document

0030690: Draw Harness - provide XDisplay command for displaying XDE document

XDisplay - added new command displaying XDE document in ViewerTest map of object:
> XDisplay Doc [label1 [label2 [...]]] [-explore {on|off}] [-docPrefix {on|off}] [-names {on|off}]
>              [-noupdate] [-dispMode Mode] [-highMode Mode]

vstate - added NULL checks.
vdisplay now prints error on attempt to specify unsupported display mode.
verase, vremove now raise Tcl exception on attempt to hide non-existing object.
verase, vremove, vdir now accept name masks like "verase b*".
vremove and vdir output is now consistent to verase command (space-separated list of removed objects).