(svn r4493) Newgrf : Action 04. Beginning of implementation.

Some TODOs left, but the core is there.
Thanks to Peter1138 for code, advice and patience
And to Patchman for letting us define a lot of langids :)

newgrf_text.h

@@ -0,0 +1,41 @@
+/* $Id$ */
+#ifndef NEWGRF_TEXT_H
+#define NEWGRF_TEXT_H
+
+/** @file
+ * Header of Action 04 "universal holder" structure and functions
+ */
+
+#define MAX_LANG 28
+
+/**
+ * Element of the linked list.
+ * Each of those elements represent the string,
+ * but according to a different lang.
+ */
+typedef struct GRFText {
+	byte langid;
+	char *text;
+	struct GRFText *next;
+} GRFText;
+
+
+/**
+ * Holder of the above structure.
+ * Putting both grfid and stringid togueter allow us to avoid duplicates,
+ * since it is NOT SUPPOSED to happen.
+ */
+typedef struct GRFTextEntry {
+	uint32 grfid;
+	uint16 stringid;
+	GRFText *textholder;
+} GRFTextEntry;
+
+
+StringID AddGRFString(uint32 grfid, uint16 stringid, byte langid, const char *text_to_add);
+StringID GetGRFStringID(uint32 grfid, uint16 stringid);
+char *GetGRFString(char *buff, uint16 stringid);
+void CleanUpStrings(void);
+void SetCurrentGrfLangID(const char *iso_name);
+
+#endif /* NEWGRF_TEXT_H */