Split textwraps, move more textboxes to new system

This splits the text wrapping functionality of Graphics::textboxwrap to
a new function textboxclass::wrap, and with this new function, some more
text boxes can be moved to the new TEXTTRANSLATE_FUNCTION system.
Namely, Game Saved (specifically the game failing to save text box),
instructional text boxes in Space Station 1, and the Intermission 1
instructional text boxes.

desktop_version/src/Textbox.h

@@ -95,6 +95,8 @@ public:
 
     void centertext(void);
 
+    int wrap(int pad);
+
     void copyoriginaltext(void);
 
     void applyoriginalspacing(void);