Create Filtering object, add helpers

SabreTools.Filter/Operation.cs

@@ -0,0 +1,20 @@
+namespace SabreTools.Filter
+{
+    /// <summary>
+    /// Determines what operation is being done
+    /// </summary>
+    public enum Operation
+    {
+        /// <summary>
+        /// Default value, does nothing
+        /// </summary>
+        NONE,
+        
+        Equals,
+        NotEquals,
+        GreaterThan,
+        GreaterThanOrEqual,
+        LessThan,
+        LessThanOrEqual,
+    }
+}