[cla][patch] dojox.image.Slideshow IE resize fix

[matsuri]

fixing the _fitsize functionality

• img = new Image() enables IE to get/set img.height/width
• set img.width/height without "px" postfix

weakening stack overflow issue

• setTimeout 1ms for loadNextImage throws only a stack overflow error of first image instead of nearly everytime an image is loaded
• i couldnt find out y the initial error is thrown, so there is still a bug

[dante]

i misinterpreted this ticket. the stackoverflow issue persists, and is a separate ticket.

[dante]

(In [14621]) fixes #7256 - patch proxy for matsuri [cla] approved by sos [cla]