Update jquery.infinitescroll.js

On line 264-266, added a new RegEx match to take into account WordPress posts with numbers appended to them (WordPress does this since some posts may have the same title). Examples would be:

http://www.example.com/this-post/
http://www.example.com/this-post-2/

There was a glitch when the infinite scroll would encounter a post with the latter URL. Full info on glitch is detailed here:

http://stackoverflow.com/questions/23769257/glitch-in-wordpress-single-php-infinite-scroll-pagination-loop