WxMap: Update API to Accept ISO Time Durations

[jardizzo]

This will enable users to invoke WxMap with any desired time increment appropriate for the data being visualized. The current command-line argument is limited to hours.

[jardizzo]

WxMap was updated to allow ISO time durations to be specified as a time increment while preserving the default hourly units assumption. WxMap can now increment over years, months, days, hours, minutes and seconds. Seconds may not work with the current data service however.