[js] simplify cw.log implementation
There's no need to rebuild and array and join its content, just
call console.log with ``arguments``.
The only trick is that console.log must be called on a console instance.
<div id="ajaxroot">
<div class="ajaxHtmlHead">
<script src="http://foo.js" type="text/javascript"> </script>
<link rel="stylesheet" type="text/css" media="all" href="qunit.css" />
</div>
<h1>Hello</h1>
</div>