Added the ability to use json data from igsdb.herokuapp.com as measured product data. - Changed calc_u and calc_shgc to calc_u_optics_file, calc_u_shgc_file, calc_u_json_data and calc_shgc_json data. So user is responsible for selecting the correct function based on the data source.
1.0.0
Initial public release with example product files (optics format).