Latest 3.3.x release.
Changes are:
- new: scr.col.brd in theme.ini;
- new: rtl support (_USE_HARFBUZZ and new SDL_ttf needed);
- new: instead.tiny flag in tiny;
- enh: emscripten 2.0.12 ready;
- enh: gtk3 build is enabled by default;
- enh: APPIMAGE define;
- enh: new anigif realization (LGPL code removed);
- enh: lua5.4 ready;
- enh: fixes and cleanups in code.