Single events missing value code

Fills in values for missing events with Constants.UJNDEFINED rather than
skipping when a single event is not found.
Deterministic runs

Fixes deterministic computation problems introduced with EVENT-YEAR
being used to determine alternative name and WAT model.
Changed xunits from "Weibull" to ""

Change corresponds to HEC freq data plotting defaults.
Adjusted runs from 1 to 11 to 1 to 101.