Many serialization improvements:

• Don't serialize form fields without a name attribute
• Don't try to serialize <input type=file>
• Fix serializing <select multiple> values
• Fix serialize()/serializeArray() on empty Zepto collections
• Serialize null values as empty strings in $.param()
• Support functions as values in $.param()
• Only deserialize number from data-* attributes if that doesn't change its string representation

Other fixes:

• Improve detection of whether an $.ajax request is crossDomain or not
• Fix find(falsey) to return an empty Zepto collection instead of an empty Array
• Fix css() on empty Zepto collection causing exceptions when "ie" module is not included
• Ensure that $.animate completion callback doesn't fire prematurely if the animation is configured with a delay
• Actually focus() & blur() elements when these events are manually triggered
• Fix installing auto-cancelling event handlers with shorthands such as submit(false), click(false)
• Prevent removeClass/addClass from affecting window objects
• Enable removeAttr to remove space separated list
• Ensure recognition of Safari on Windows