Updated default memory manager for other platform.

NTwain/Internals/LinuxMemoryManager.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace NTwain.Internals
+{
+    class LinuxMemoryManager : IMemoryManager
+    {
+        #region IMemoryManager Members
+
+        public IntPtr Allocate(uint size)
+        {
+            return Marshal.AllocHGlobal((int)size);
+        }
+
+        public void Free(IntPtr handle)
+        {
+            Marshal.FreeHGlobal(handle);
+        }
+
+        public IntPtr Lock(IntPtr handle)
+        {
+            return handle;
+        }
+
+        public void Unlock(IntPtr handle)
+        {
+            // no op
+        }
+
+        #endregion
+    }
+}