Include Zepto library so that JS on error pages still works.
No animate() in Zepto.
Use correct header height for scrolling back up.
Improve selectors, jQuery style.
Use event delegation.

This way, we avoid binding the event handler to all lines. Instead, we
bind to the container and simply pass on control to the targeted frame.
Use on() instead of delegate().

delegate() is deprecated.
Merge pull request #128 from franzliedke-pulls/bundled-jquery

Offline jQuery / Zepto