Allow multi-faceted image cache refresh

[nasser85]

Currently, when a user clicks on the "View Nasa Images from this Location" link in the info window of a marker, one of two things happens:

• If a location and its image(s) are not present in the GoogleMap component cache - the latitude and longitude of the location are passed along to the NASA Earth Imagery API where a GET request is made for url link to the image. This image is not only displayed in the image window modal but the url is also saved alongside the location in the cache for future access.
• If a location and its image(s) are present in the GoogleMap component cache - the relevant url is accessed from the cache and displayed.

The problem here is that the url comes with a token attached to it that has an expiration. As a result, it is possible for someone to access a location that exists in the cache that pulls up an image with a broken src. Therefore we would have to build a robust set of refresh cache functions or a class to refetch urls and update the cache in the event that a image token has expired.