Issue #2845747 by amaria: ResponsiveImageFormatter' not found in FlexsliderResponsiveFormatter.php on line 25

Fixes problem with upper/lower case sample file extensions. Puts example module in the correct package.

Fixes flexslider field formatter in views. Adds/Uses defaults class containing true library defaults

Upgrades flexslider view style. Reverts item output back to string from render array. Minor cleanup.

Optionset. Add the flexslider field formatter.