Initial commit
First commit of 'jcamp.py' into the repository. I've modified it considerably, so it is not yet tested.
Modified the JCAMP_calc_xsec() utility function to look for a 'partial_pressure' entry in the header for quantifying the absorption cross-section.'
Added infrared spectra JDX files from the NIST infrared spectral database.
Modified JCAMP_reader() to properly parse not only infrared spectra files but also UVVis spectra, Raman spectra, and Mass spectra. Running the jcamp.py by itself tests this functionality.
Added folders of JDX containing Raman spectra, UV/Vis spectra, and Mass spectra.
Moved the 'xfactor' and 'yfactor' corrections into JCAMP_reader() from jcamp_xsec_calc(). Also fixed a bug where the code was failing to parse the example files in the repository.
Fixed bug in parsing when negative numbers in spectra.