Added fix for strides <= 0 (which results in division by zero).
Added fix for strides <= 0 (which results in division by zero).


OPENDAP/libdap4,OPENDAP/libdap4,OPENDAP/libdap,OPENDAP/libdap4,OPENDAP/libdap,OPENDAP/libdap4,OPENDAP/libdap4,OPENDAP/libdap,OPENDAP/libdap,OPENDAP/libdap4