add docs for CRS handling
add docs for CRS handling

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