Added polarimetric efficiency to plot and log + corrections of 2 minor bugs

• Added polarimetric efficiency to crosstalk/transmission plot, a print statement with the range of the polarimetric efficiency of the observations, and a warning in case of low polarimetric efficiency
• Corrected a bug in the checks of flux_annulus_star
• Corrected a bug that when mean combining ADI+PCA-images only the first frame of the cube was written to the FITS-files