Merge pull request #885 from jay-hodgson/SWC-1248

SWC-1248: store image file blob url reference in the client cache on upload and before save (release-35)
Merge pull request #883 from jay-hodgson/SWC-1251

SWC-1251 and SWC-1249
Merge pull request #879 from jay-hodgson/SWC-1250

SWC-1250: fix concurrent update handling, and edit state when there is an error on save
Merge branch 'release-35' into develop