IMG-596 display time and user name on image description history page
IMG-613 open history in modal window. Theme can be changed.
IMG-613 Set focus back to link
IMG-613 Set focus back to link - clean-up, sorry for multiple commits
IMG-599 use spine to get content hrefs
Test epub
Fixed sniffing of extension, gets tricked by filenames with periods in it.
Added underscores and dashes as allowed UID characters
Removed console logging
IMG-607 Switch to lazy image loading
Merge remote-tracking branch 'origin/develop' into develop
Merge for 4.6.2 release.