Updates the website to 0.12.4
Point to the ppa for nodejs
updates the install page for 0.12.4
loading-amber improvements
minor changes to the loading page
loading-amber page mostly ready
Move the warning to the bottom of the page.
better explanation for the popup issue.
Updates to documentation with the new amber-cli npm package
Adds a warning about popups being blocked in the getting started page too
Embeds the introduction video by @sebastiansastre