MYST3: Change transitions triggering to be more precise
MYST3: Add support for the Japanese version subtitles

Iconv is used to convert from CP 932 to Unicode.
Since iconv support is not yet included in ResidualVM,
this does not work properly, but at least it does not
crash anymore.

The game does not provide the TTF font required to render
the Japanese characters. The user must provide a font
named "msgothic.ttf".