v0.7.4: drop smart-mode, always return the title-matched still
The previous smart mode returned empty when the local title matched
TMDB's title at the same (S, E) position, on the theory that the
built-in provider would deliver the right image in that case. In
practice this meant the language-aware entry was missing from the
image picker for the common in-sync case, so the picker would just
show the built-in's untagged still and the user couldn't tell whether
the plugin was working at all.
Now the plugin always returns the title-matched still tagged with the
preferred language. For in-sync libraries it's the same image the
built-in would have returned, but with a language tag so it ranks at
the top of OrderByLanguageDescending. For out-of-sync libraries it's
the title-correct image instead of the built-in's positional fallback.
Cleans up the now-unused PositionToNormalisedTitle map from the
ShowEpisodeData record.
README updated; log message renamed from "alt-order match" to "title
match" to reflect that it fires for in-sync episodes too.