Port to Qt5's internal JSON parser

Unfortunately the QVariant conversions need to be done as we still need
to handle the XML part

src/libdanbooru/utils.cpp

@@ -20,11 +20,14 @@
  *
  */
 
+// Own
+
 #include "utils.h"
 
 // Qt
 
-#include <qjson/parser.h>
+#include <QJsonDocument>
+#include <QJsonObject>
 #include <QXmlStreamReader>
 
 // KDE
@@ -156,17 +159,15 @@ namespace Danbooru {
 
     QVariant parseDanbooruResult(QByteArray data, bool* result)
     {
-        QJson::Parser parser;
 
-        bool ok;
+        QJsonDocument parsed = QJsonDocument::fromJson(data);
 
-        QVariant postData = parser.parse(data, &ok);
-
-        if (!ok) {
-            *result = ok;
+        if (parsed.isNull()) {
             return QList<QVariant>();
         }
 
+        QVariant postData = parsed.toVariant();
+
         *result = true;
 
         return postData;