Update Less Analyzer to be able to handle imports of files

Related to magento#73 - option 2, if you wish to see a more indepth writeup

The Less Analyzer class cannot handle Less files that import css as the object they convert into mean the $node->path->value is a Link_Tree_Quoted object and not a string castable value, so we add an additional check for if we are a CSS quoted file or if value is an object which contains another value and use that instead (In the off chance similar future issues may arise with new objects)

Author: furan917

src/Analyzer/Less/Analyzer.php

@@ -128,7 +128,11 @@ private function getNodes(LessRegistry $registry): array
                     if (property_exists($node, 'name')) {
                         $nodeKey = $node->name;
                     } elseif (property_exists($node, 'type') && property_exists($node, 'path')) {
-                        $nodeKey = $node->type . ' with value: \'' . $node->path->value . '\'';
+                        if ($node->path->value instanceof \Less_Tree_Quoted || property_exists($node->path->value, 'value')) {
+                            $nodeKey = $node->type . ' with value: \'' . $node->path->value->value . '\'';
+                        } else {
+                            $nodeKey = $node->type . ' with value: \'' . $node->path->value . '\'';
+                        }
                     } else {
                         $nodeKey = get_class($node);
                     }