IceProxyMCVersionInfo>>#gtDisplayString should be removed

[MarcusDenker]

gtDisplayString has no senders anymore and has a deprecation rewrite on the level of Object

--> it can be removed

[tinchodias]

I was going to only push a commit removing this method but after browsing the code of that class, I preferred to comment other removal candidates in the same class:

• gtDisplayOn:
• asSpotterCandidateLink

Should we just remove them or there are candidate names for renaming? I mean, for the new inspector / new spotter.

[Ducasse]

Martin normally I migrated all the gtDisplayOn: to displayStringOn:
I should remove all the gtDisplay:.
there should be no reference to gtDisplayOn: (in my PR there were none). Now may be spec got merged and some of my changes got reverted. I do not know.