Split display name into first and last

Remove all support for directly entering the display
name.
Minor fix for getting focus after text editor expands.

Test:
Tested the following editor scenarios:
  1) new contact
  2) edit writable raw contact
  3) edit read-only raw contact (joins a new writable raw contact to it)
     a) Not editing the name and saving doesn't save the new writable
        raw contact
     b) making edits to the name and swapping accounts saves those edits
     c) swapping around a lot doesn't create multiple writable raws
  4) edit aggregate w/ 1 writable and 1 read-only raw contact
  5) edit aggregate w/ 2 writable raw contacts
  6) swapping accounts doesn't lose entered data

Bug: 21758689
Change-Id: I8d97083ae1e0db1031ee8e4d860f65d77022a1a1