Cleanup and bugfixes

I found a bug which caused the plugin to return a different set of elements when used in container mode. This is fixed by returning `this` explicitly.

Moreover, I fixed all the issues which were flagged by jshint and introduced a hash called `settings` and used jQuery's `.extend()` function to deal with the plugin options. Also, when no value for the speed is provided, a default of 400 ms (same as `minSpeed`).

Lastly I updated the minified versions of the plugin and removed a conflict marker in the `<title>` element of the default example file.