Do not default to the undockPrefix of "Insta" if there is no setting defined for UndockPrefix, this allows one to turn off the feature by leaving it blank.

If somehow we manage to set UndockBookmark to a bookmark that is not in local (really should not happen), log the issue and continue without crashing the client by trying to warp to a bookmark in another system =/\
This also adds a sanity check in Entitycache.WarpTo() so that we will never try to warp to something that is more than 1/2 a light year away (31500+ AU)