This commit adds a small and simplistic C wrapper around boost's locale library as intern/locale, and heavily simplifies/reduces Blender's own i18n code (under blenfont/ dir). And it adds back UI translation on windows' official builds (with msvc)!
Note to platform maintainers: iconv and gettext (libintl) can now be removed from precompiled libs (not gettext binaries, under windows, of course ;) ).
Note to MinGW32/64 users: boost_locale lib has not yet been uploaded for those build env, please disable WITH_INTERNATIONAL for now (hopefully will be fixed very soon, have contacted psy-fy).