Move some classes and restructure.

src/WireMock/Matchers/Request/IRequestMatcher.cs

@@ -0,0 +1,19 @@
+using JetBrains.Annotations;
+
+namespace WireMock.Matchers.Request
+{
+    /// <summary>
+    /// The RequestMatcher interface.
+    /// </summary>
+    public interface IRequestMatcher
+    {
+        /// <summary>
+        /// Determines whether the specified RequestMessage is match.
+        /// </summary>
+        /// <param name="requestMessage">The RequestMessage.</param>
+        /// <returns>
+        ///   <c>true</c> if the specified RequestMessage is match; otherwise, <c>false</c>.
+        /// </returns>
+        bool IsMatch([NotNull] RequestMessage requestMessage);
+    }
+}