bump version to 3.4.0

Author: Doug Black

src/main/java/com/twilio/sdk/TwilioRestClient.java

@@ -46,7 +46,7 @@
 public class TwilioRestClient {
 
 	/** The Constant VERSION. */
-	private static final String VERSION = "3.3.16";
+	private static final String VERSION = "3.4.0";
 
 	/** The endpoint. */
 	private String endpoint = "https://api.twilio.com";