Fix FxCop messages and run FxCop on each build.

src/Microsoft.VisualStudio.Validation/Assumes.InternalErrorException.cs

@@ -22,7 +22,7 @@ namespace Microsoft
         /// </summary>
         [Serializable]
         [SuppressMessage("Microsoft.Design", "CA1064:ExceptionsShouldBePublic", Justification = "Internal exceptions should not be caught.")]
-        private class InternalErrorException : Exception
+        private sealed class InternalErrorException : Exception
         {
             /// <summary>
             /// Initializes a new instance of the <see cref="InternalErrorException"/> class.
@@ -48,7 +48,7 @@ namespace Microsoft
             /// Initializes a new instance of the <see cref="InternalErrorException"/> class.
             /// </summary>
             [DebuggerStepThrough]
-            protected InternalErrorException(SerializationInfo info, StreamingContext context)
+            private InternalErrorException(SerializationInfo info, StreamingContext context)
                 : base(info, context)
             {
             }

src/Microsoft.VisualStudio.Validation/Microsoft.VisualStudio.Validation.csproj

@@ -15,6 +15,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
+    <RunCodeAnalysis>true</RunCodeAnalysis>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <ErrorReport>prompt</ErrorReport>