Make auto-scroll behavior optional

_(first off, thanks very much for the excellent library. it's the bee's knees)_

As mentioned in #50, the auto-scroll behavior is particularly irksome if you have multiple consoles on one page.

This patch introduces a new (optional) parameter to the `jqconsole` constructor (& jquery function) that turns off auto-scroll.

If the argument is omitted, default behavior remains the same as before.

Cheers!

[EDIT: removed compiled & minified files, fixed camel-case variable that should be underscore'd]

~~[EDIT2: actually, this breaks auto-scrolling the `<pre>` element as well. Fix will be coming soon.]~~
I'm not sure I understand what you mean. The variable `auto_scroll` isn't in scope here. It's only in scope of the constructor. I set it as an instance property since so we can access it here without having to explicitly pass it to every function that ends up calling `@_ScrollToEnd`

(just did a quick sanity check to make sure it wasn't a CoffeeScript quirk - [here's the error I get](http://f.cl.ly/items/0Q0j470T1z1p370N3X1T/Screen%20Shot%202014-06-19%20at%2011.30.12%20AM.png))