Added the possibility for protocol providers to specify type of proxy they would like to use.

src/net/java/sip/communicator/service/protocol/ProtocolProviderFactory.java

@@ -88,6 +88,14 @@ public abstract class ProtocolProviderFactory
      */
     public static final String PROXY_PORT = "PROXY_PORT";
 
+    /**
+     * The name of the property under which we store the the type of the proxy
+     * stored against the PROXY_ADDRESS property. Exact type values depend on
+     * protocols and among them are socks4, socks5, http and possibly others.
+     */
+    public static final String PROXY_TYPE = "PROXY_TYPE";
+
+
     /**
      * The name of the property under which we store the name of the transport
      * protocol that needs to be used to access the proxy.