Fixing a problem with languages (like Hungarian) where it's legal to use
a two-letter tile or two single-letter tiles to play the same word. When
words are seen, or searched for, as char-arrays, there are
duplicates. Current code crashes, but there's also risk the user gets
unexpected behavior. Crash is fixed, and foundation laid for better UX,
by doing all searches for tile arrays. If a search string translates to
more than one tile array the user must choose. For that choice to make
sense it's now possible to translate tile[] to char[] with a delimiter
between the tile strings.
digraph tile when at the end of a prefix so that e.g. GORIL in Catalan
will list GORIL·LA (rather than nothing since GORIL, ending with the L
tile, is not a prefix.)
