Appion

The default ctffind4.py value on the attached image fails during ctffind4 rotational average

**warning(Image::ComputeRotationalAverageOfPowerSpectrum): unable to rescale 1D average of experimental power
forrtl: error (73): floating divide by zero

parameters example:

 --ampcontrast=0.07 --fieldsize=1024 --resmin=50 --resmax=10 --defstep=0.1 --numstep=50 --dast=0.05

passes if resmax=8

While this a problem of ctffind4, we should handle the error and give proper error log.