Doesn't do the exact same (you'd have to add a new entry everytime, rather than point *.dev to localhost) but https://addons.mozilla.org/en-US/firefox/addon/hostadmin/ is easier to set up. It'll flush the dns cache everytime its changed.
No, you don't have to add a new entry every time, you just set it up and now absolutely.anything.dev points to localhost. When editing /etc/hosts you have to add a line for every hostname.
