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.

I included the built & minified files here, but that may not be desirable (since I likely am using different versions of coffee-script & uglify). If you don't want them included, I'll happily take them out.

Cheers!