Changeset 43

Mostly changes related to a bug fix. The HISTORY information was not being written to FITS files other than the first from each tape file. This was due to PSRFits::initialise() resetting the newFile flag. I have fixed this by storing the filename and command-line information in the PSRFits class, and enabling the PSRFits::writeHistory...() functions to access this information. These functions are then called by the PSRFits::initialise() function.