Upgrade to jquery-color 2.0pre. Fixes #6910 - Trying to animate the b…

…ackground color of a document fragment can easily fail. Fixes #5215 - Effects color: Add support for rgba animations. Fixes #4372 - Animate backgroundColor to 'transparent'. Fixes #5393 - getColor reports inaccurate color for transparent elements in Webkit. Fixes #3806 - Feature request: expose getRGB and getColor.