Remove edit tab from the DOM if it's hidden

Fixed bug 64142, works around bug 65292

Bug: 64142
Bug: 65292
Change-Id: I31d8f7b149d657a678ed6ebc56b92305934f34bc
On file pages, only replace the (local) image description when saving

Instead of overwriting everything else on the page (including the thumbnail!)

Bug: 65349
Change-Id: Ib6c4928646d6d278e29fbe31ae1902b0dc3b146a
Merge "On file pages, only replace the (local) image description when saving"
Merge "Remove edit tab from the DOM if it's hidden"