chessbox: Get rid of strings for level 8/9/10

We've been limited to level 7 since approximately forever, so
there's no point in wasting translation strings on anything higher.

Change-Id: Idee0f1f0aa1b99d9efdcaa34d0d3130a54e1628e

apps/lang/english.lang

···
   </voice>
 </phrase>
 <phrase>
-  id: LANG_CHESSBOX_LEVEL_8
-  desc: in the chessbox game level selection
-  user: core
-  <source>
-    *: "Level 8: 1 move / 15 min"
-  </source>
-  <dest>
-    *: "Level 8: 1 move / 15 min"
-  </dest>
-  <voice>
-    *: "Level 8, 1 move per 15 minutes"
-  </voice>
-</phrase>
-<phrase>
-  id: LANG_CHESSBOX_LEVEL_9
-  desc: in the chessbox game level selection
-  user: core
-  <source>
-    *: "Level 9: 1 move / 60 min"
-  </source>
-  <dest>
-    *: "Level 9: 1 move / 60 min"
-  </dest>
-  <voice>
-    *: "Level 9, 1 move per 60 minutes"
-  </voice>
-</phrase>
-<phrase>
-  id: LANG_CHESSBOX_LEVEL_10
-  desc: in the chessbox game level selection
-  user: core
-  <source>
-    *: "Level 10: 1 move / 600 min"
-  </source>
-  <dest>
-    *: "Level 10: 1 move / 600 min"
-  </dest>
-  <voice>
-    *: "Level 10, 1 move per 600 minutes"
-  </voice>
-</phrase>
-<phrase>
   id: LANG_CHESSBOX_PGN_PARSE_ERROR
   desc: in the chessbox game viewer
   user: core

apps/plugins/chessbox/chessbox.c

···
 #include "opening.h"
 #include "chessbox_pgn.h"
 
+#define MAX_LEVEL 7
+
 /* type definitions */
 struct cb_command {
     int type;
···
                         ID2P(LANG_CHESSBOX_LEVEL_4) ,
                         ID2P(LANG_CHESSBOX_LEVEL_5) ,
                         ID2P(LANG_CHESSBOX_LEVEL_6) ,
-                        ID2P(LANG_CHESSBOX_LEVEL_7) ,
-                        ID2P(LANG_CHESSBOX_LEVEL_8) ,
-                        ID2P(LANG_CHESSBOX_LEVEL_9) ,
-                        ID2P(LANG_CHESSBOX_LEVEL_10) };
+                        ID2P(LANG_CHESSBOX_LEVEL_7) };
 
 /* "While thinking" command */
 int wt_command = COMMAND_NOP;
···
 
 /* ---- set playing parameters depending on level ---- */
 static void cb_setlevel ( int lev ) {
-    Level = (lev > 7) ? 7 : ( (lev < 1) ? 1 : lev ) ;
+    Level = (lev > MAX_LEVEL) ? MAX_LEVEL : ( (lev < 1) ? 1 : lev ) ;
     switch (Level) {
         case 1 :
             TCmoves = 60;
···
             TCmoves = 40;
             TCminutes = 240;
             break;
-        case 8 :
-            TCmoves = 1;
-            TCminutes = 15;
-            break;
-          case 9 :
-            TCmoves = 1;
-            TCminutes = 60;
-            break;
-          case 10 :
-            TCmoves = 1;
-            TCminutes = 600;
-            break;
     }
     TCflag = (TCmoves > 1);
     SetTimeControl();
···
 
 /* ---- increase playing level ---- */
 static void cb_levelup ( void ) {
-    if ( Level == 7 )
+    if ( Level >= MAX_LEVEL )
         cb_setlevel ( 1 );
     else
         cb_setlevel ( Level+1 );