[projections] add visualizer_for_sensitivity.py based on...

[projections] add visualizer_for_sensitivity.py based on visualizer_for_projection_ensemble.py. add temperature_to_year.py file.
Fix max abs recurrent issue (when it was equal to zero). add one test for one fold fit, that was that due to a scale parameter that was close to zero, and was causing instabilities in the nllh value. This is fixed by changing the check for implausible in one fold fit, and by saying that if the scale parameter is close to zero then the parameter is undefined.