Fixed char access.

Author: Abramo-Bagnara

src/jquery.contextMenu.js

@@ -1206,7 +1206,7 @@ function splitAccesskey(val) {
         keys = [];
 
     for (var i=0, k; k = t[i]; i++) {
-        k = k[0].toUpperCase(); // first character only
+        k = k.charAt(0).toUpperCase(); // first character only
         // theoretically non-accessible characters should be ignored, but different systems, different keyboard layouts, ... screw it.
         // a map to look up already used access keys would be nice
         keys.push(k);