Added WinMerge support.

src/Assent/Reporters/DiffPrograms/WinMergeDiffProgram.cs

@@ -0,0 +1,27 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Assent.Reporters.DiffPrograms
+{
+    public class WinMergeDiffProgram : DiffProgramBase
+    {
+        static WinMergeDiffProgram()
+        {
+            DefaultSearchPaths = WindowsProgramFilePaths
+                .Select(p => $@"{p}\WinMerge\WinMergeU.exe")
+                .ToArray();
+        }
+
+        public static readonly IReadOnlyList<string> DefaultSearchPaths;
+
+        public WinMergeDiffProgram() : base(DefaultSearchPaths)
+        {
+
+        }
+
+        public WinMergeDiffProgram(IReadOnlyList<string> searchPaths)
+            : base(searchPaths)
+        {
+        }
+    }
+}

src/Assent/Reporters/DiffReporter.cs

@@ -19,9 +19,10 @@ static DiffReporter()
                 ? new IDiffProgram[]
                 {
                     new BeyondCompareDiffProgram(),
+                    new WinMergeDiffProgram(),
                     new KDiff3DiffProgram(),
                     new XdiffDiffProgram(),
-                    new P4MergeDiffProgram(), 
+                    new P4MergeDiffProgram(),
                     new VsCodeDiffProgram()
                 }
                 : new IDiffProgram[]