Start of factor graph port. Things don't work yet, but a lot of syntax updates towards PHP

PHPSkills/FactorGraphs/FactorGraph.php

@@ -0,0 +1,18 @@
+<?php
+namespace Moserware\Skills\FactorGraphs;
+
+class FactorGraph
+{
+    private $_variableFactory;
+
+    public function getVariableFactory()
+    {
+        return $this->_variableFactory;
+    }
+
+    public function setVariableFactory($factory)
+    {
+        $this->_variableFactory = $factory;
+    }
+}
+?>