Add location accuracy for coordinates on Post Service Request

[philipashlock]

Many devices that provide GPS coordinates can also provide the accuracy for the current reading. This can be useful information for determining how easy it will be to match the reported location with the actual location.

More info on this from SF:
http://www.sf311.org/index.aspx?page=733#ConcernedReporter

For iOS (Apple) devices there is actually a separate accuracy reading for the latitude and longitude. I'm not sure if this is the case for other devices as well. More info at:
http://developer.apple.com/library/ios/#documentation/CoreLocation/Reference/CLLocation_Class/CLLocation/CLLocation.html#//apple_ref/doc/uid/TP40007126