This fixes issue #36: you edit a tile with an image field that already has an image, you keep the current image, but on save your previous image is gone.
This replaces PR #38 with a slightly different fix, and adds tests.
This builds on PR #39 which fixes Travis. So I recommend merging that one first.
The real fix of the current PR is the last commit: 9fdd1e302ba2a8d035f7bc8a07d14f4b25feecbb. Review can focus on that one.
Coverage increased (+1.1%) to 82.299% when pulling 9fdd1e302ba2a8d035f7bc8a07d14f4b25feecbb on maurits/issue-36-the-mysterious-case-of-the-disappearing-images into efde9085ceb3c1e633df0ccccefe7f4e18c7fe13 on master.
This fixes issue #36: you edit a tile with an image field that already has an image, you keep the current image, but on save your previous image is gone.
This replaces PR #38 with a slightly different fix, and adds tests.
This builds on PR #39 which fixes Travis. So I recommend merging that one first. The real fix of the current PR is the last commit: 9fdd1e302ba2a8d035f7bc8a07d14f4b25feecbb. Review can focus on that one.