Revert "supprt ALTGR key event"

This reverts commit 079504a6d256001664a09c70ca69c4b742171aeb.

include/input.js

@@ -69,7 +69,6 @@ function getKeysymSpecial(evt) {
             case 17        : keysym = 0xFFE3; break; // CONTROL
             //case 18        : keysym = 0xFFE7; break; // Left Meta (Mac Option)
             case 18        : keysym = 0xFFE9; break; // Left ALT (Mac Command)
-            case 225       : keysym = 0xFFEA; break; // ALTGR
 
             case 112       : keysym = 0xFFBE; break; // F1
             case 113       : keysym = 0xFFBF; break; // F2