Rev 1504: New reduction log, improved WCS and pupilghost

Rev 1504 (2015-08-24)

• Improved WCS solution for some frames where QR < 0.9 found a valid solution, but the faster algorithm in QR 1.1 yielded some wrong, yet seemingly good, WCS solution
• Improved algorithm to compute Pupilghost templates by auto-centering and auto-rotating all constituent frames rather than relying on center positions derived by hand.
• New reduction log added to the output file (both primary and OTA headers);
  Example:

          Reduction log
  
  _OVERSCN= 'successful'         / overscan subtraction
  _XTALK  = 'successful'         / crosstalk correction
  _GAIN   = 'not selected'       / explicit gain correction
  _BIAS   = 'not selected'       / bias subtraction
  _DARK   = 'not selected'       / dark correction
  _FLAT   = 'not selected'       / flatfielding
  _ILLUMCR= 'not selected'       / illumination correction
  _BADPXLS= 'not selected'       / bad pixel masks applied
  _EXTNORM= 'not selected'       / normalize to counts per sec
  _PERSIST= 'not selected'       / persistency masking
  _SATURAT= 'not selected'       / saturation trail masking
  _WCSDIST= 'successful'         / import WCS distorion
  _COSMICS= 'not selected'       / cosmic ray rejection
  _PGHOST = 'not selected'       / pupilghost removal
  _FRINGE = 'attempted'          / fringe removal
  _WCSCAL = 'successful'         / astrometric calibration
  _NONSDRL= 'not selected'       / non-sidereal correction
  _PHOTCAL= 'not selected'       / photometric ZP calibration
  _SOFTBIN= 'not selected'       / software binning