fadeIn/fadeOut/fadeTo leaves inline style "filter" behind in IE

[Myrlyn]

Using fadeIn/fadeOut leaves an inline "filter" key in the style attribute for elements effected by the fade. This causes a few problems:

1) The inline filter without a value makes the element opaque even if the CSS says it should be semi-transparent.

2) Causes a brief "flash" upon subsequent fadeIn/fadeOut/fadeTo calls where the element is briefly fully opaque.

A rewrite of the three methods that fixes this problem can be found here:

​http://malsup.com/jquery/fadetest.html

[snover]

#4845 is a duplicate of this ticket.

[snover]

Duplicate of #6652.