Refactoring xfer logic from twainsession out.

NTwain/ITwainSession.cs

@@ -0,0 +1,22 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain
+{
+    /// <summary>
+    /// General interface for a TWAIN session.
+    /// </summary>
+    public interface ITwainSession : ITwainState, ITwainOperation
+    {
+        /// <summary>
+        /// Gets the supported caps for the currently open source.
+        /// </summary>
+        /// <value>
+        /// The supported caps.
+        /// </value>
+        IList<CapabilityId> SupportedCaps { get; }
+    }
+}