Remove unused variables in the TIGHT server init

This commit removes some unused variables in the TIGHT server init
section of the server init handler, replacing them with documenting
comments and calls to rQskipBytes.

Fixes #440.

include/rfb.js

@@ -920,18 +920,17 @@ var RFB;
                 var totalMessagesLength = (numServerMessages + numClientMessages + numEncodings) * 16;
                 if (this._sock.rQwait('TightVNC extended server init header', totalMessagesLength, 32 + name_length)) { return false; }
 
-                var i;
-                for (i = 0; i < numServerMessages; i++) {
-                    var srvMsg = this._sock.rQshiftStr(16);
-                }
+                // we don't actually do anything with the capability information that TIGHT sends,
+                // so we just skip the all of this.
 
-                for (i = 0; i < numClientMessages; i++) {
-                    var clientMsg = this._sock.rQshiftStr(16);
-                }
+                // TIGHT server message capabilities
+                this._sock.rQskipBytes(16 * numServerMessages);
 
-                for (i = 0; i < numEncodings; i++) {
-                    var encoding = this._sock.rQshiftStr(16);
-                }
+                // TIGHT client message capabilities
+                this._sock.rQskipBytes(16 * numClientMessages);
+
+                // TIGHT encoding capabilities
+                this._sock.rQskipBytes(16 * numEncodings);
             }
 
             // NB(directxman12): these are down here so that we don't run them multiple times