Add static map image

I was able to add a static map image to the vendor detail page, but ran in
to some problems with the back button and reseting the src for the static
map image.
Fix back button problems and map loading

I was able to fix the back button problems, by refering to the correct
screen element in the on back cmd. I was also able to solve the map
loading problem, because it seems that I only loaded the map when a user
navigated from the list page to the detail page, and forgot to reset the
map when the detail page was navigated to by the productsdetail page.