madrobby/zepto — pull request #575 by baccigalupi (2012-08-31 16:01:15+00:00)
Title: Setting css opacity to 0 will result in opacity style being removed

The css if test for removing a style is `value ==''` which of course will test positive for 0 values. This has implications for other kinds of styles. For example, if the border-width is set in an element to a non-zero value in the css file and we need to use the css function to add a 0 width on the element in some circumstance, this passes through.