Fixed indentation before }
Removed useless variable declaration (twice)
Added comments to better explain what's happening in the core functions.
Fixed comments on top
Removed iOS 5 workaround (not used anymore).
Converted all the .bind jQuery methods to .on methods (faster, safer).
Shorthand for document ready.
Fixed indentation. Added a comment before .each.
Replaced potentially dangerous "this" usage with "self".
Ignored .idea files (webstorm editor).
Using $self.data instead of $self.attr("data-" + ...)
Added settings.show_on_appear and managed it, the ugly way
settings.show_on_appear managed with less code repetition
Fixed behaviour when show_on_appear === true
Refactored code: private functions moved to an outer scope, without making them globals.
Changed default placeholder with empty 1x1 gif.
Added the "enabled_on_appear" test html.
Added enabled_on_appear.html test
Added enabled_on_appear.html test