It should be `{. xxxx=yyy }`, not `{_ xxxx=yyy }`.
Only test/test-element-attributes-markdown.html were using `{_`,
simply in order to test the ability, for the user, to define a _different_ pattern.

Also add a description about the solarized theme.

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