Weather tweaks: include time in response, reverse wind direction arrows

This alters the response of the .weather command so that it includes the time of the weather report.  A typical response intro will change from "Yahoo! Weather - Austin, TX:" to "Austin, TX at 11:50 pm CST:", which seems nicer and more useful to me.

This also reverses all the arrows displayed for wind direction.  Currently, for example, 337.5 - 22.5 degrees is represented by an up arrow, suggesting motion towards the north, but those numbers mean that the wind is coming *from* the north.