Merge branch 'develop' into release/1.7.1
Merge pull request #694 from akvo/issue/664

[#664] Fix NPE when no `sourceId` exists
[#702] RELEASE NOTES v1.7.1
Merge pull request #703 from akvo/issue/702

[#702] RELEASE NOTES v1.7.1
Merge branch 'release/1.7.1'
Merge branch 'master' into develop