Updates to support Environment Canada provider

Code updates to support a new weatherobject element called precipitationUnits. For the 'forecast' and 'hourly' UI, the weather module will use this new element if it is not null (i.e. a provider has pushed some value into this object element). If the element is null, then default 'units' processing will still occur. This allows a provider to have a customn unit of measure for precipitation - e.g. Env Canada will use mm for rain and cm for snow.

modules/default/weather/weatherobject.js

@@ -28,6 +28,7 @@ class WeatherObject {
 		this.rain = null;
 		this.snow = null;
 		this.precipitation = null;
+		this.precipitationUnits = null;
 		this.feelsLikeTemp = null;
 	}