Update jquery.responsiveimages.js

Add options for container and skip_invisible

Better handling of top/bottom left/right position of element
inspired by http://www.appelsiini.net/projects/lazyload
to allow onepage horizontal layouts with jquery.ascensor.js
http://kirkas.ch/ascensor/#Home

Allow external call to $.fn.responsiveimages.update()
eg on ascensor page transition
Merge branch 'master' of https://github.com/s-leger/bootstrap_package into s-leger-master
Merge branch 's-leger-master'
[TASK] Minify responsiveimages.js and and cleanup