Assegnate 5 su 5 stelle

please, add default paste clipboard text as image for markdown.
example:
1) ![_selection_](_clipboard_)
2) ![Image](_clipboard_)

Questa recensione riguarda una versione precedente (0.4.1.1-signed) del componente aggiuntivo. 

I agree on #1, since it follows the "Make selection URL" logic. Not sure about the second.

Currently working on 0.5.0, mostly to make the add-on working with e10s.