Change the computed fields mechanism to loop over the fields in Python
Change the computed fields mechanism to loop over the fields in Python

This should allow for more sophisticated, albeit slower, demos.

ContinuumIO/dynd-python,insertinterestingnamehere/dynd-python,pombredanne/dynd-python,izaid/dynd-python,pombredanne/dynd-python,aterrel/dynd-python,ContinuumIO/dynd-python,pombredanne/dynd-python,insertinterestingnamehere/dynd-python,ContinuumIO/dynd-python,insertinterestingnamehere/dynd-python,mwiebe/dynd-python,michaelpacer/dynd-python,cpcloud/dynd-python,michaelpacer/dynd-python,pombredanne/dynd-python,izaid/dynd-python,mwiebe/dynd-python,mwiebe/dynd-python,cpcloud/dynd-python,aterrel/dynd-python,izaid/dynd-python,aterrel/dynd-python,izaid/dynd-python,mwiebe/dynd-python,michaelpacer/dynd-python,cpcloud/dynd-python,michaelpacer/dynd-python,insertinterestingnamehere/dynd-python,aterrel/dynd-python,cpcloud/dynd-python,ContinuumIO/dynd-python