added partial VFS support - enough to read static data from any source

ExternalLibs/ttvfs/VFSLoader.h

@@ -0,0 +1,31 @@
+// VFSLoader.h - late loading of files not in the tree
+// For conditions of distribution and use, see copyright notice in VFS.h
+
+#ifndef VFSLOADER_H
+#define VFSLOADER_H
+
+#include "VFSDefines.h"
+
+VFS_NAMESPACE_START
+
+class VFSFile;
+
+// VFSLoader - to be called if a file is not in the tree.
+class VFSLoader
+{
+public:
+    virtual ~VFSLoader() {}
+    virtual VFSFile *Load(const char *fn) = 0;
+};
+
+class VFSLoaderDisk : public VFSLoader
+{
+public:
+    virtual ~VFSLoaderDisk() {}
+    virtual VFSFile *Load(const char *fn);
+};
+
+VFS_NAMESPACE_END
+
+
+#endif