The font module kept a global "currently selected font" set by
font_select() and implicitly used when drawing. Make it stateless by
introducing a FontSpec {type, weight, size} that font_render_text() /
font_draw_text() and gfx_drawString() take directly.
Make FontWeight a two-valued enum and normalize the 1-9 weight to it
in commandZB().
Removes font_select(), ags_setFont() and ags_setFontWithWeight().
This adds "Unicode mode", in which scenarios can be written in any
language. xsys35c 1.2.0 and later can produce Unicode scenarios.
- nact->encoding represents the current scenario encoding. The initial
value is SJIS, and ZU command changes it to UTF8.
- Use conversion macros that switch the behavior by the scenario
encoding. For example, toUTF8() calls sjis2utf() if the scenario
encoding is SJIS, and calls strdup() if it is UTF8.
- Fix various string processing functions to work with UTF8.