Add support for Minecraft Service DNS Records

- Add DnDns library for performing DNS queries
 - Add query method for SRV record
 - Resolve Minecraft services

This allows resolving actual server addresses for
servers using SRV records on their domain names

SRV records are basically DNS redirection eg:

  myserver.net -> srv1.myserver.net:12345

Should solve #186 reported by sammyvsparks and many others.

MinecraftClient/Protocol/Dns/Enums/NsClass.cs

@@ -0,0 +1,94 @@
+/**********************************************************************
+ * Copyright (c) 2010, j. montgomery                                  *
+ * All rights reserved.                                               *
+ *                                                                    *
+ * Redistribution and use in source and binary forms, with or without *
+ * modification, are permitted provided that the following conditions *
+ * are met:                                                           *
+ *                                                                    *
+ * + Redistributions of source code must retain the above copyright   *
+ *   notice, this list of conditions and the following disclaimer.    *
+ *                                                                    *
+ * + Redistributions in binary form must reproduce the above copyright*
+ *   notice, this list of conditions and the following disclaimer     *
+ *   in the documentation and/or other materials provided with the    *
+ *   distribution.                                                    *
+ *                                                                    *
+ * + Neither the name of j. montgomery's employer nor the names of    *
+ *   its contributors may be used to endorse or promote products      *
+ *   derived from this software without specific prior written        *
+ *   permission.                                                      *
+ *                                                                    *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS*
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT  *
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS  *
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE     *
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,*
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES           *
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR *
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) *
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,*
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)      *
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED*
+ * OF THE POSSIBILITY OF SUCH DAMAGE.                                 *
+ **********************************************************************/
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace DnDns.Enums
+{
+    /// <summary>
+    /// RFC 1035:
+    /// 
+    /// 3.2.4. CLASS values
+    /// 
+    /// CLASS fields appear in resource records.  The following CLASS mnemonics
+    /// and values are defined:
+    /// 
+    /// IN              1 the Internet
+    /// 
+    /// CS              2 the CSNET class (Obsolete - used only for examples in
+    ///                 some obsolete RFCs)
+    /// 
+    /// CH              3 the CHAOS class
+    /// 
+    /// HS              4 Hesiod [Dyer 87]
+    /// 
+    /// 3.2.5. QCLASS values
+    /// 
+    /// QCLASS fields appear in the question section of a query.  QCLASS values
+    /// are a superset of CLASS values; every CLASS is a valid QCLASS.  In
+    /// addition to CLASS values, the following QCLASSes are defined:
+    /// 
+    /// *               255 any class
+    /// </summary>
+    public enum NsClass : byte
+    {
+        /// <summary>
+        /// Cookie??                - NOT IMPLEMENTED
+        /// </summary>
+        INVALID = 0,
+        /// <summary>
+        /// // Internet (inet), RFC 1035
+        /// </summary>
+        INET = 1,
+		/// <summary>
+        /// MIT Chaos-net, RFC 1035 - NOT IMPLEMENTED
+		/// </summary>
+        CHAOS = 3,
+        /// <summary>
+        /// MIT Hesiod, RFC 1035    - NOT IMPLEMENTED
+        /// </summary>
+        HS = 4,
+        /// <summary>
+        /// RFC 2136 - None
+        /// prereq sections in update requests -- NOT IMPLEMENTED
+        /// </summary>
+        NONE = 254,
+        /// <summary>
+        /// Any QCLASS only, Wildcard match, RFC 1035   - IMPLEMENTED for INET only
+        /// </summary>
+        ANY = 255
+    }
+}