Old Visu firefox extension

[Seijboldt]

Hi Seijboldt,
the extension works perfectly. 

A few suggestions for improvement:
1. When you select multiple elements, copy them, and then paste them again, it would be nice if the newly pasted elements were all automatically selected.
2. Option to delete multiple selected elements

Added both suggestions + distribute in grid. Gif doesnt show the popup dialog though.
When deleting multiple objects you gotta hit enter/confirm and when distributing in grid you have to select column count.

Cleaned up the extension menu for selecting allowed site to remove misunderstandings in what is/what isnt whitelisted.

Pushing update now, should be live within 10 minutes. In theory it should auto-update from my server if all works as it should!