Initial commit of changes for 1.2.3. This includes:

- Scripting support: Allows for recording and playback of mouse/keyboard input and various system control actions.  Simple (i.e. basic) scripting format.

- Fix for stale packets left in ethernet input queue; packets received by pcap while Alto's receiver is off are discarded.

- Mouse input made more accurate, and tweaked to avoid Alto microcode bug that causes erroneous mouse inputs under very rare circumstances on real hardware, but much more frequently under emulation.

- Small code cleanup here and there.  Moved many UI strings to resources, many more to go.

Contralto/Scripting/ScriptReader.cs

@@ -0,0 +1,66 @@
+using Contralto.Logging;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Contralto.Scripting
+{
+    public class ScriptReader
+    {
+        public ScriptReader(string scriptPath)
+        {
+            _scriptReader = new StreamReader(scriptPath);
+        }
+
+        public ScriptAction ReadNext()
+        {
+            if (_scriptReader == null)
+            {
+                return null;
+            }
+
+            //
+            // Read the next action from the script file,
+            // skipping over comments and empty lines.
+            //
+            while (true)
+            {
+                if (_scriptReader.EndOfStream)
+                {
+                    // End of the stream, return null to indicate this,
+                    // and close the stream.
+                    _scriptReader.Close();
+                    _scriptReader = null;
+                    return null;
+                }
+
+                string line = _scriptReader.ReadLine().Trim();
+
+                // Skip empty or comment lines.
+                if (string.IsNullOrWhiteSpace(line) ||
+                    line.StartsWith("#"))
+                {
+                    continue;
+                }
+
+                try
+                {
+                    return ScriptAction.Parse(line);
+                }
+                catch(Exception e)
+                {
+                    Log.Write(LogComponent.Scripting, "Invalid script; error: {0}.", e.Message);
+                    _scriptReader.Close();
+                    _scriptReader = null;
+                    return null;
+                }
+            }
+        }
+
+        private StreamReader _scriptReader;
+
+    }
+}