Added setters to the location class in order to avoid creating a new SunriseSunsetCalculator every time a new location arrives (useful for mobile devices)

In mobile devices, an app may receive new locations quite frequently. Previously, the only way of updating sunrise/sunset times whenever a new location arrived was to instantiate a new SunriseSunsetCalculator object. With this changes, we can just access the SunriseSunsetCalculator's location using "getLocation()", update the coordinates, and calculate again.