* Added support for lazy loading of images
** All images (profile, content) have a placeholder src image by default
** Loads images by setting 'src' value with original image value, stored in 'data-src'
** Upon 'update' or 'scroll' event, iterates through all post items that haven't loaded images, and if visible, loads all images in the item
** Added some basic styles to pending images, so can tell there's something there
** Fixes #33