2018-07-17: succssfully reproduce TBO images

there's now a "package" for a variety of different figures to be produced. I incorporated the numerical integration into a function so that it's earily  callable within loops

original release by Matthew B Rowley

Original release used in data analysis for "Global Analysis of Perovskite Photophysics Reveals Importance of Geminate Pathways" (DOI: 10.1021/acs.jpcc.6b11547)