Add modal with block info (like themes)

[perandre]

Just like the standard popup for themes, we can do the same for blocks. I realize that all info can actually come from package.json (except possible the description?):

This is useful for promoting the author, and also get get a better view of the screenshot.

[perandre]

Perhaps @SofiaSousa has input on this as well.

[foadyousefi]

That was implemented and is available since version 1.0.5.

I will close this issue.