Add CDATA section to coffee_script_tag

Nobody has claimed this yet.

Is there any reason for `coffee_script_tag` to not render JS inside a CDATA section as `javascript_tag` would do?

``` erb
<%= javascript_tag do%>
<%= coffee_script do %>

if 2 < 0
alert('uh?')

<% end %>
<% end %>
```

the code above would render the following html that is friendly to any xml/html parser:

``` html

//<![CDATA[

(function() {

if (2 < 0) {
alert('uh?');
}

}).call(this);

//]]>

```

instead of doing the same `coffee_script_tag` renders the code without wrapping it in `CDATA` turning html to not be well formed anymore (eg. `2 < 0`):

``` erb
<%= coffee_script_tag do%>
if 2 < 0
alert('uh?')
<% end %>
```

``` html

(function() {

if (2 < 0) {
alert('uh?');
}

}).call(this);

```

Thanks

Start with the coffee_script_tag helper and compare its output with javascript_tag, as shown in the issue examples. Check how the generated CoffeeScript becomes JavaScript, then make the rendered script use the CDATA wrapping demonstrated in the expected HTML. Done means expressions containing < produce well-formed HTML.

Written by the indexing model from the issue text.