Add vendor-kwargs to WMTS constructor.
Add vendor-kwargs to WMTS constructor.

bird-house/OWSLib,menegon/OWSLib,robmcmullen/OWSLib,kalxas/OWSLib,Jenselme/OWSLib,geopython/OWSLib,geographika/OWSLib,mbertrand/OWSLib,jachym/OWSLib,JuergenWeichand/OWSLib,jaygoldfinch/OWSLib,b-cube/OWSLib,kwilcox/OWSLib,gfusca/OWSLib,tomkralidis/OWSLib,dblodgett-usgs/OWSLib,jaygoldfinch/OWSLib,ocefpaf/OWSLib,KeyproOy/OWSLib,QuLogic/OWSLib