Initial commit

Conversion of the UWP app into a .NET Core app for portability. Requires .NET Core 2.0 and C# 7.1

Messages/ChallengeString.cs

@@ -0,0 +1,40 @@
+using System;
+
+namespace ScreenLogicConnect.Messages
+{
+    public class ChallengeString : HLMessage
+    {
+        private String challengeString;
+
+        public static ChallengeString QUERY(short senderID)
+        {
+            return new ChallengeString(senderID, (short)14);
+        }
+
+        private ChallengeString(short senderID, short msgID)
+                : base(senderID, msgID)
+        {
+        }
+
+        public ChallengeString(sbyte[] header, sbyte[] data)
+                : base(header, data)
+        {
+        }
+
+        public ChallengeString(HLMessage msg)
+                : base(msg)
+        {
+        }
+
+        protected override void decode()
+        {
+            this.startIndex = 0;
+            this.challengeString = HLMessageTypeHelper.extractString(this.data, ref startIndex);
+        }
+
+        public String getChallengeString()
+        {
+            return this.challengeString;
+        }
+    }
+}