function buffer( dtype, size ) {
	if ( dtype === 'generic' ) {
		return generic( size );
	}
	if ( dtype === 'binary' ) {
		return binary( size );
	}
	return typedarray( dtype, size );
}
Returns a contiguous linear ndarray data buffer.

@param {string} dtype - data type
@param {NonNegativeInteger} size - buffer size
@returns {(Array|TypedArray|Buffer|null)} data buffer

@example
var buf = buffer( 'float64', 3 );
// returns <Float64Array>[ 0.0, 0.0, 0.0 ]