Update popit-api to latest master
Update popit-api to latest master

Includes the following features/fixes:

- Added `include_root` parameter to API listing pages
- Pagination metadata such as total results page no. etc

openstate/popit,Sinar/popit,openstate/popit,openstate/popit,mysociety/popit,Sinar/popit,Sinar/popit,mysociety/popit,mysociety/popit,mysociety/popit,openstate/popit,mysociety/popit,Sinar/popit