Version 0.4.0 - Unpoly

Changes

Error messages no longer take over the entire screen.
Don't create redundant ghost elemants when not transitioning.
Remove nested log grouping, as group headers cannot be filtered away in Chrome DevTools.
.up-current is now also applied to links with an [up-source] attribute.
Errors are now shown within the page body (instead of opening an input-blocking alert).
Rename up.cache module to up.proxy.
up.proxy defaults are now configurable.
Add [up-instant] attribute to follow a link on mousedown instead of click.
Add [up-preload] attribute to preload a link on hover.
Don't boot with jQuery versions older than 1.9.
up.form.observe() detects changes on browsers that do not fire input events.
Line breaks in tooltips are no longer allowed, as it breaks positioning.
[up-tooltip] can now read the tooltip text from an existing [title] attribute.
up.util.debug() no longer crashes when there are no placeholders in the message.
Format logging with nested groups.
You can now attach data to elements using the new [up-data] attribute. The attribute value is parsed as JSON and passed to compilers.
More robust implementation of up.form.observe().
Starting new animations and transitions now cancels existing motion.