Feature request: Check on different viewport widths

[attiks]

For example: click targets on mobile should be bigger so they are easier to click

[attiks]

As far as I can tell it is checking with a small viewport, or without media query support

[attiks]

I had a look at the code, AFAIK this is the flow meaning the options have to follow the same path

cli.js parses the arguments, so we could add an option like --screen=1024x768
cli.js calls index.js and passes the options (opts)
cli.js starts phantomjs using audits.js passing the url as a parameter
audits.js passes the argument to get the url

So we need a way to pass the screen on the command line, so we can add something like this inside audits.js

webpage.viewportSize = {
  width: 1024,
  height: 768
};

• What are sane defaults to provide?
• Does this approach sounds sane?

[addyosmani]

Can this be closed as of #19?

[attiks]

Sure