Fixing the way 404 pages and script/navigation links are handled.

Now, if the there's 0 or 1 page, the script and navigation links won't be inserted in the page. The 404 error pages are also properly returned when there's no itens to be paged.

fixes #6
Adding the navigationLinkText option, used to set the text displayed in the navigation link. The default value is "next".

Note: This link is usually hidden when infinite-scroll is enabled. It is supposed to be visible and used only when javascript is disabled.
Fix formatting
Updated to infinite scroll with default options configured