Updated default memory manager for other platform.

NTwain.Net35/NTwain.Net35.csproj

@@ -109,6 +109,9 @@
     <Compile Include="..\NTwain\Internals\IWinMessageFilter.cs">
       <Link>Internals\IWinMessageFilter.cs</Link>
     </Compile>
+    <Compile Include="..\NTwain\Internals\LinuxMemoryManager.cs">
+      <Link>Internals\LinuxMemoryManager.cs</Link>
+    </Compile>
     <Compile Include="..\NTwain\Internals\TentativeStateCommitable.cs">
       <Link>Internals\TentativeStateCommitable.cs</Link>
     </Compile>

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
+    }
+}

NTwain/NTwain.csproj

@@ -70,6 +70,7 @@
     <Compile Include="ImageTools.cs" />
     <Compile Include="Internals\InternalMessageLoopHook.cs" />
     <Compile Include="Internals\ITwainSessionInternal.cs" />
+    <Compile Include="Internals\LinuxMemoryManager.cs" />
     <Compile Include="Interop\BITMAP.cs" />
     <Compile Include="Interop\MESSAGE.cs" />
     <Compile Include="Internals\TransferLogic.cs" />

NTwain/PlatformInfo.cs

@@ -34,6 +34,8 @@ namespace NTwain
 
             if (IsWindows)
             {
+                _defaultMemManager = new WinMemoryManager();
+
                 var newDsmPath = Path.Combine(Environment.SystemDirectory, Dsm.WIN_NEW_DSM_NAME);
 #if NET35
                 var oldDsmPath = Path.Combine(Environment.GetEnvironmentVariable("windir"), Dsm.WIN_OLD_DSM_NAME);
@@ -63,6 +65,8 @@ namespace NTwain
             }
             else if (IsLinux)
             {
+                _defaultMemManager = new LinuxMemoryManager();
+
                 ExpectedDsmPath = Dsm.LINUX_DSM_PATH;
                 DsmExists = File.Exists(ExpectedDsmPath);
                 IsSupported = DsmExists && IsOnMono;
@@ -71,8 +75,6 @@ namespace NTwain
             {
                 // mac? not gonna happen
             }
-
-            _defaultMemManager = new WinMemoryManager();
         }
 
         /// <summary>