Add transport security support for net.tcp

* Add support for SecurityMode.Transport in net.tcp
* Add in support for client X509Certificates for WCF Core
* Add StreamSecurityBindingElement
* Add SslStreamSecurity and supporting components
* Add WindowsStreamSecurity stubs
* Import IdentityModel code around X509 cert, tokens
* Disable failing tests due to WindowsStreamSecurity being stubbed now (dotnet#301)
* Add support for DnsEndpointIdentity

Fixes dotnet#9, dotnet#12, dotnet#81

src/System.Private.ServiceModel/src/Resources/Strings.resx

@@ -6747,4 +6747,7 @@
   <data name="ConfigurationFilesNotSupported" xml:space="preserve">
     <value>Configuration files are not supported.</value>
   </data>
-</root>
+  <data name="X509ChainBuildFail" xml:space="preserve">
+    <value>The X.509 certificate {0} chain building failed. The certificate that was used has a trust chain that cannot be verified. Replace the certificate or change the certificateValidationMode. {1}</value>
+  </data>
+</root>

src/System.Private.ServiceModel/src/System/IdentityModel/Claims/Claim.cs

@@ -6,6 +6,9 @@
 using System.Runtime;
 using System.Runtime.Serialization;
 using System.Security.Cryptography;
+#if FEATURE_CORECLR // X509Certificates
+using System.Security.Cryptography.X509Certificates;
+#endif // FEATURE_CORECLR
 using System.Security.Principal;
 using System.ServiceModel;
 
@@ -160,7 +163,15 @@ public static Claim CreateUriClaim(Uri uri)
             return new Claim(ClaimTypes.Uri, uri, Rights.PossessProperty);
         }
 
+#if FEATURE_CORECLR // X509Certificates
+        public static Claim CreateX500DistinguishedNameClaim(X500DistinguishedName x500DistinguishedName)
+        {
+            if (x500DistinguishedName == null)
+                throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("x500DistinguishedName");
 
+            return new Claim(ClaimTypes.X500DistinguishedName, x500DistinguishedName, Rights.PossessProperty, ClaimComparer.X500DistinguishedName);
+        }
+#endif // FEATURE_CORECLR
 
         public override bool Equals(object obj)
         {