warping: accept warping options METHOD=NO_GEOTRANSFORM and DST_METHOD=NO_GEOTRANSFORM to run gdalwarp on ungeoreferenced images

git-svn-id: https://svn.osgeo.org/gdal/trunk@27811 f0d54148-0727-0410-94bb-9a71ac55c965
Warp: fix Cubic and Bilinear resampling to work correctly with downsizing (#3740)

git-svn-id: https://svn.osgeo.org/gdal/trunk@27812 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_with_coverage