CSS: Drop the float mapping from cssProps

Firefox 35 and newer support style.float directly.

Closes #3569

src/css.js

@@ -201,9 +201,7 @@ jQuery.extend( {
 
 	// Add in properties whose names you wish to fix before
 	// setting or getting the value
-	cssProps: {
-		"float": "cssFloat"
-	},
+	cssProps: {},
 
 	// Get and set the style property on a DOM Node
 	style: function( elem, name, value, extra ) {