gis/rasterio: Wrap README at 72 columns.

Signed-off-by: B. Watson <yalhcru@gmail.com>

gis/rasterio/README

@@ -1,9 +1,11 @@
-Fast and direct geospatial raster I/O for Python programmers who use Numpy.
+Fast and direct geospatial raster I/O for Python programmers who use
+Numpy.
 
-This package is aimed at developers who want little more than to read raster
-images into Numpy arrays or buffers, operate on them in Python (or Cython), and
-write the results out to new GeoTIFF files.
+This package is aimed at developers who want little more than to read
+raster images into Numpy arrays or buffers, operate on them in Python
+(or Cython), and write the results out to new GeoTIFF files.
 
-Rasterio employs GDAL under the hood for file I/O and raster formatting.
+Rasterio employs GDAL under the hood for file I/O and raster
+formatting.
 
 Optional dependencies: boto3.