Get window height for older IEs
Get dialog position for older IEs
Older IEs do not have "bind," so use lambdas instead.
Older browsers do not have forEach, so iterate using while instead.
Older browsers do not have "classList," but there is no reason to use it on a newly-created element anyways.
When older IEs throw an error at setting the background-color using RGBA, use something they understand.
Set zoom=1 on the dialog element, in order to trigger hasLayout for older IEs and show the element.
Do not try to dispatch a custom "close" event in older browsers (such as IE) that do not support doing so.
Find the index of the dialog in the stack, for those browsers that do not support "indexOf"
Catch exceptions thrown by IE when attempting to focus on elements.
Do not attempt to throw a nonexistent error type.
Set opacity styling for backdrop in a way that older IE can use.
Reposition dialog before focusing on it, so scrolling does not happen prematurely.
Prevent dialog top from going past top of screen.
Make constants local vars.
Add cancelable option for cancel CustomEvent

The cancel event is allowed to do prevent default action to stop the dialog from closing on pressing Esc. 
It is missing the cancelable option from the CustomEvent in cancelDialog() but allowed with the initEvent fallback.
resolving conflicts
dropping IE7 css support
Merge branch 'matzko-ie7-compatibility'
simple wrap behavior to contain focus in dialog