Change Details - 15 min Hourly Cig stats based on 5-min METARs

13-Feb-2018 (production and beta)
Found and fixed a remaining yn <-> ny problem that caused bias to actually be 1/bias.

Corrected yn <-> ny problem in the statistics. Also, fixed up dieoff curves to work on 15 min increments. And, used more sensible treatment of dates (foreach date in dates). Routines changed: get_ceil_stats.cgi, DisplayFrame, CurveParameters.

Prepared by Bill Moninger,
Last modified: Tue Feb 13 23:26:02 GMT 2018