adjust filename RegEx to include http or https
Merge pull request #34 from seanhellwig/master

Adjust filename RegEx to support http and https
README fussing
Release v0.6
Change version number to 'dev'
Configurable timeout (fixes #37)
Move --user-agent help into network section
Better default user agent
Allow waiting for async JS to capture the image

With this change, webkit2png is able to wait for arbitrary asynchronous
JavaScript to finish before capturing the screenshot. Use code such as:

    webkit2png.stop();  // wait for start() before capturing
    $.get("/path/to/handler", function(data) {
        displayData(data);
        webkit2png.start();
    });

and the picture won't be captured until the AJAX request returns. (I
stole the names 'start' and 'stop' from QUnit:
http://api.qunitjs.com/category/async-control/.)
Merge pull request #39 from spicyj/async-js

Allow waiting for async JS to capture the image