Add translation support

Extracted translations from the Japanese, French, Italian, German and Spanish ROMS.
Messages have been reformatted to use @ for formatting (similar to how it is handled in-game). A demo translation function _ is also provided, but not made use of in battle.js. To actually enable translations, in addition to loading the big translation file and setting a language in Config, every game message in battle.js must be refactored to use translation, e.g. "Pointed stones dug into " + poke.getLowerName() + "!" should be rewritten to _("Pointed stones dug into @0!", poke.getLowerName());