- Changed fallback font to 'sans serif:pixelsize=12'

- Fixed convertfonts to account for $LANG
- Fixed convertfonts logic a bit and no longer output slant and weight if
  they are the default ones (medium and roman)
- Applied Pascal's fix for GNUstep menus (modified to also include submenus)
  Still this is not the proper fix, as it can't differentiate between
  submenus and other windows at the floating window level. Correct fix needs
  some extra hints to be set by GNUstep on menus.

WINGs/wfont.c

@@ -13,7 +13,7 @@
 #include <X11/Xlocale.h>
 
 
-#define DEFAULT_FONT "sans-serif:pixelsize=12"
+#define DEFAULT_FONT "sans serif:pixelsize=12"
 
 #define DEFAULT_SIZE WINGsConfiguration.defaultFontSize
 
@@ -38,7 +38,7 @@ xlfdToFcPattern(char *xlfd, int size)
     wfree(fname);
 
     if (!pattern) {
-        wwarning(_("invalid font: %s. Using default %s"), xlfd, DEFAULT_FONT);
+        wwarning(_("invalid font: %s. Trying '%s'"), xlfd, DEFAULT_FONT);
         pattern = FcNameParse(DEFAULT_FONT);
     }