Improve map view with small thumbnails rather than pins

[damianmoore]

So far it was easiest to show pins on the map for geo-tagged photos. This means you currently have to click each pin to view the thumbnail. Instead of pins the thumbnails should be displayed with border-radius: 50% to make them circular. Clicking a thumbnail should take you straight to the photo detail view. Clustered group icons should remain unchanged. Here is a mock-up of how the thumbnails should look on a mobile screen.

[GyanP]

Task Completed and pushed on branch 265-update-map-pin.

[damianmoore]

Merged as of 595b555