Replacing gettext i18n backend by boost::locale one.

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).

source/creator/CMakeLists.txt

@@ -469,20 +469,6 @@ elseif(WIN32)
 		DESTINATION ${TARGETDIR}
 	)
 
-	if(WITH_INTERNATIONAL AND (NOT WITH_MINGW64))
-		install(
-			FILES ${LIBDIR}/gettext/lib/gnu_gettext.dll
-			DESTINATION ${TARGETDIR}
-		)
-
-		if(NOT CMAKE_CL_64)
-			install(
-				FILES ${LIBDIR}/iconv/lib/iconv.dll
-				DESTINATION ${TARGETDIR}
-			)
-		endif()
-	endif()
-
 	if(WITH_PYTHON)
 		set_lib_path(PYLIB "python")
 		install(
@@ -530,7 +516,7 @@ elseif(WIN32)
 	endif()
 
 	if(CMAKE_CL_64)
-		# gettext and png are statically linked on win64
+		# png is statically linked on win64
 		install(
 			FILES ${LIBDIR}/zlib/lib/zlib.dll
 			DESTINATION ${TARGETDIR}
@@ -987,6 +973,10 @@ endif()
 		list_insert_after(BLENDER_SORTED_LIBS "cycles_kernel" "cycles_kernel_osl")
 	endif()
 
+	if(WITH_INTERNATIONAL)
+		list(APPEND BLENDER_SORTED_LIBS bf_intern_locale)
+	endif()
+
 	foreach(SORTLIB ${BLENDER_SORTED_LIBS})
 		set(REMLIB ${SORTLIB})
 		foreach(SEARCHLIB ${BLENDER_LINK_LIBS})