Merge pull request json-schema-org#64 from pboettch/master

Add links to valijson and json-schema-validator - both written in C++

Author: Relequestual

implementations.html

@@ -84,6 +84,8 @@ <h2>Validators</h2>
 	<li>C++
 	<ul>
 		<li><a id="link-impl-wjelement" href="https://github.com/petehug/wjelement-cpp">wjelement-cpp</a> - <em>supports version 4</em> (LGPLv3)</li>
+		<li><a id="link-impl-valijson" href="https://github.com/tristanpenman/valijson">Header-only C++ library for JSON Schema validation</a> - <em>supports only version 4</em> (BSD-2-Clause)</li>
+		<li><a id="link-impl-modern-c++-validator" href="https://github.com/pboettch/json-schema-validator">Modern C++ JSON schema validator</a> - <em>supports only version 4</em> based on JSON for Modern C++ (MIT)</li>
 	</ul>
 	</li>
 	<li>Haskell