[#180] Add rsr.utils.right_now_in_akvo()

Add right_now_in_akvo() in utils to be used for the Right now in Akvo
box on the home page and the API resource right_now_in_akvo.
[#180] Use rsr.utils.right_now_in_akvo() on RSR home page

Edit the index view to use right_now_in_akvo() for the data that
goes into the Right now in Akvo box

Edit the index.html template to use the context fields from
right_now_in_akvo()
[#180] Add RightNowInAkvoResource to the API

RightNowInAkvoResource returns the data needed for the Right now in
Akvo box on the RSR home page.
Merge branch 'develop' of github.com:akvo/akvo-rsr into develop