I think I'm done.

Changes from last version:
The translation/object tabs are gone, replaced by a "Show unique object names" button. (With all those other filters and sorters, having it as tabs made little sense)
Factories can sort by number of goods (it counts outputs first, then inputs). That's arbitrary, but just as good as only input, only output, or the sum; having several seemed to overdo it.
Since groundobj_edit was put into the game, it's now part of this patch.
Much cleaner extend_edit.cc - I seperated the layout from the content, so it should be easier to navigate and change the placement of things going forward.
Image is underneath description, and in the scrolly element. I 'hacked' the resizing by defining ten columns, then spanning the right container over 9 of them - the game tries to attribute space evenly to all 10.
An issue (which I hope Dwachs can fix): If the scrollbar appears, it will be there every other update even if nothing is cut off.
About translations... *sigh* I did the changes. First thing I see: "Sort by" was translated, in English, to "sort passenger/freight by"...
I don't want this translation issue to stop the patch from being added, so I added a patch reusing old strings, but also a version using new strings.