Convert structures (nested) to text file and back

This function takes a non-flat structure and writes it to a text file. Execute text to remake struc

Convert any flat or arbitrarily non-flat structure to a text file. to rebuild the structure, highlight and execute the text in the file.

(Currently only implemented for Structure with fields of type 'structure','[nxm] numeric scalars and matrices', and 'strings'

Add functionality for cells, f handles, etc as you like (space provided). Please update/repost if you make upgrades to this file.

Thank you.
Dave