Add future warnings for read_mask, read_band.
Add future warnings for read_mask, read_band.

brendan-ward/rasterio,youngpm/rasterio,perrygeo/rasterio,njwilson23/rasterio,kapadia/rasterio,clembou/rasterio,johanvdw/rasterio,brendan-ward/rasterio,perrygeo/rasterio,perrygeo/rasterio,clembou/rasterio,kapadia/rasterio,johanvdw/rasterio,johanvdw/rasterio,youngpm/rasterio,brendan-ward/rasterio,kapadia/rasterio,youngpm/rasterio,clembou/rasterio,njwilson23/rasterio,njwilson23/rasterio