Merge pull request #1877 from OCHA-DAP/staging

Pull request for merging staging into prod for Sprint 41
Hotfix for adding more checks on the ebola page

- checking that sparkline data is not empty
- checking items have a date set
changing version to 0.5.7
Merge pull request #1881 from OCHA-DAP/hotfix-sparkline-checks

Hotfix sparkline checks
Merge pull request #1882 from OCHA-DAP/prod

Pull request for merging hotfix from prod in staging ( Sprint 41 )