Implemented ALU, most of Memory state machine.

Contralto/Memory/Memory.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Contralto.Memory
+{
+    public class Memory : IMemoryMappedDevice
+    {
+        public Memory()
+        {
+            _mem = new ushort[0xffff];
+        }
+
+        public ushort Read(int address)
+        {
+            return _mem[address];
+        }
+
+        public void Load(int address, ushort data)
+        {
+            _mem[address] = data;
+        }
+
+        private ushort[] _mem;
+    }
+}