Use get_full_name and get_short_name.

Use these instead of first_name and last_name, as the latter may
disappear at some point of time in the future. At least this is what I
observed in the current timeline. Unfortunately, the TARDIS time/date
indicator was malfunctioning, so don't know what year this happened.

Change-Id: Ia7173251ea55ebb6a15b40d41085352f4fc5eaa9