Update references to RFC 2616

Replace references to the old RFC 2616 (HTTP 1.1) with references
to the new RFCs 7230 to 7235.

This commit also deprecates:
 - HttpStatus.USE_PROXY
 - HttpStatus.REQUEST_ENTITY_TOO_LARGE in favor of HttpStatus.PAYLOAD_TOO_LARGE
 - HttpStatus.REQUEST_URI_TOO_LONG in favor of HttpStatus.URI_TOO_LONG

Issue: SPR-12067

spring-core/src/main/java/org/springframework/util/MimeTypeUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -309,8 +309,8 @@ public abstract class MimeTypeUtils {
 	 * <blockquote>audio/basic == text/html</blockquote> <blockquote>audio/basic ==
 	 * audio/wave</blockquote>
 	 * @param mimeTypes the list of mime types to be sorted
-	 * @see <a href="http://tools.ietf.org/html/rfc2616#section-14.1">HTTP 1.1, section
-	 *      14.1</a>
+	 * @see <a href="http://tools.ietf.org/html/rfc7231#section-5.3.2">HTTP 1.1: Semantics
+	 * and Content, section 5.3.2</a>
 	 */
 	public static void sortBySpecificity(List<MimeType> mimeTypes) {
 		Assert.notNull(mimeTypes, "'mimeTypes' must not be null");