Fix jQuery compatibility issues in jquery.color.js

Fix two issues which caused jquery.color to be incompatible with
the currently used jQuery version:
* The $.fx.step hook in jquery.color.js relied on fx.state which is
  not provided by current jQuery. This commit replaces it with
  a manual flag (the same logic is used in the official jquery.color
  plugin).
* It used $.curCSS which has been replaced by $.css.

Change-Id: I3aa0d912b21da40167124c646fb1b35beb277a33
Merge "Fix jQuery compatibility issues in jquery.color.js"