Twenty Eleven: Fix up the color picker JS. Use a separate color swatch rather...

Twenty Eleven: Fix up the color picker JS. Use a separate color swatch rather than the input background. While cool, it doesn't have suffficient contrast. Also set farbtastic as a JS dependency. see #17198.

git-svn-id: https://core.svn.wordpress.org/trunk@17737 1a063a9b-81f0-0310-95a4-ce76da25c4cd