added WMS, TMS, and WMTS tests for mixed mode
added WMS, TMS, and WMTS tests for mixed mode

mapproxy/mapproxy,Anderson0026/mapproxy,vrsource/mapproxy,drnextgis/mapproxy,procrastinatio/mapproxy,camptocamp/mapproxy,faegi/mapproxy,procrastinatio/mapproxy,geoadmin/mapproxy,faegi/mapproxy,olt/mapproxy,geoadmin/mapproxy,camptocamp/mapproxy,mapproxy/mapproxy,kaiCu/mapproxy,kaiCu/mapproxy,Anderson0026/mapproxy,drnextgis/mapproxy,vrsource/mapproxy,olt/mapproxy