Absorption / MD / Cumulant Test

[ChristopherAMyers]

Write test for Absorption / MD / Cumulant spectra

• sbsorption spectra
• spectral density
• raman

Also need to include Ohomic solvent model

[ChristopherAMyers]

We need a Herzberg-Teller compatible trajectory dataset in order to add HT tests. The current test set is using the PYP trajectory from the examples, but this has only two columns for energy and oscillator strength only.

The tests for linear absorption with 2nd and 3rd order cumulant are other wise done