use 'url()'-free path when specifying parallax image, refactor so that parallax is applied to background class, remove unused attributes #595

Enhanced the pointer.
Cleaned up the code.
Added additional optional parameters.
Updated documentation.

modified:   README.md
modified:   index.html
modified:   plugin/leap/leap.js

Updated README.md to mention the leap plugin.
Removed leap settings from index.html.
Better variable naming in leap.js

modified:   README.md
modified:   index.html
modified:   plugin/leap/leap.js

Added "touch" config property