Convert outgoing netCDF arrays to big-endian

Changeset 76a983e removed the explicit conversion of all outgoing
datatypes into big-endian format (e.g. see page 10 of
http://earthdata.nasa.gov/sites/default/files/esdswg/spg/rfc/esds-rfc-011/ESDS-RFC-011v1.00.pdf)

This changeset converts the type to big-endian during the array
creation in createVariable by calling the dtype.newbyteorder
function with the argument "B" for Big endian.

scipy/io/netcdf.py

@@ -290,7 +290,7 @@ def createVariable(self, name, type, dimensions):
         if (typecode, size) not in REVERSE:
             raise ValueError("NetCDF 3 does not support type %s" % type)
 
-        data = empty(shape_, dtype=type)
+        data = empty(shape_, dtype=type.newbyteorder("B")) #convert to big endian always for NetCDF 3
         self.variables[name] = netcdf_variable(data, typecode, size, shape, dimensions)
         return self.variables[name]