all spectral tests have been implemented. Validation still needed, especially for polar or night scenes

This reverts commit 09ec38da.

finally implemented the Visible_Thresholds_Test. It definitely needs a closer look to make sure everything works as intended

11-12um Thin Cirrus Test has been implemented for all scene. Results still need to be verified, but look reasonable

Surface_Temperature_Test roughly implemented. code runs but function and implementation need to be polished... a lot