output format for scan step size

This is a ridiculously trivial request, but I would like to suggest that the output format for the scan step size (variable DSTEP) be changed from F9.1 to F9.3. This would be lines 111 and 124 in ctffind3.f and ctftilt.f, respectively.

The reason for this request is that we often have a pixel size (e.g. CCD data) and a corresponding scan step size has to be calculated on the fly. With only one significant digit after the decimal point, the scan step that is written to the output file will be rounded and it's impossible to recover the original pixel size from the magnification and scan step.