Improved gestational age calculator

Thanks to user feedback, I made a few changes to the GA calculator tool:
  • starts off with default day of interest to TODAY, rather than separately reporting results for TODAY
  • reports both chronologic age and either corrected age or time until due date, for the date of interest in years / months / days (helpful for infant follow-up clinic)
  • reports when first ROP exam would be due for all initial gestational ages (to include babies born at >31 weeks, but with birth weight <1500 grams)