Refactor: Replace font namespace implementation with PathDirectory

Font names are now represented as Uri within the collection itself.
Also a directory hierarchy may be defined within each namespace.

Statistical information useful for analyzing efficency of the font
namespace hashes can be retrieved in _DEBUG builds using ccmd fontstats

doomsday/engine/portable/include/fonts.h

@@ -38,11 +38,14 @@
 
 struct ded_compositefont_s;
 
+// Substrings in Font names are delimited by this character.
+#define FONTDIRECTORY_DELIMITER '/'
+
 /// Register the console commands, variables, etc..., of this module.
 void Fonts_Register(void);
 
 /// Initialize this module.
-void Fonts_Init(void);
+void Fonts_Initialize(void);
 
 /// Shutdown this module.
 void Fonts_Shutdown(void);
@@ -89,7 +92,7 @@ ddstring_t** Fonts_CollectNames(int* count);
 font_t* Fonts_ToFont(fontnum_t num);
 
 /// @return  Unique name associated with the specified Font.
-fontnum_t Fonts_ToIndex(font_t* font);
+fontnum_t Fonts_ToFontNum(font_t* font);
 
 /// @return  Font associated with @a uri else @c NULL.
 font_t* Fonts_FontForUri(const Uri* uri);

doomsday/engine/portable/src/con_busy.c

@@ -288,7 +288,7 @@ static void Con_BusyPrepareResources(void)
         font_t* font = Fonts_LoadExternal(fonts[fontIdx].name, fonts[fontIdx].path);
         if(NULL != font)
         {
-            busyFont = Fonts_ToIndex(font);
+            busyFont = Fonts_ToFontNum(font);
             FR_SetFont(busyFont);
             FR_LoadDefaultAttrib();
             busyFontHgt = FR_SingleLineHeight("Busy");

doomsday/engine/portable/src/dd_main.c

@@ -1466,7 +1466,7 @@ int DD_Main(void)
     Sys_Init();
     F_Init();
 
-    Fonts_Init();
+    Fonts_Initialize();
     if(!isDedicated)
     {
         FR_Init();