ISSUE-87: invoking open() when readyState is not 0, 1 or 4

ISSUE-87: invoking open() when readyState is not 0, 1 or 4

http://www.w3.org/2005/06/tracker/webapi/issues/87

Raised by: Anne van Kesteren
On product: XMLHttpRequest

Currently the specificatoin defines open for when readyState is 0 (or 
1...) (you go to 1) and "If open() is invoked when readyState is 4 (Loaded) all 
members of the object must be set to their initial values."

It doesn't say anything regarding what happens when you invoke it when 
readyState is 2 or 3. Does the request have to be aborted? Is the call to 
open() ignored? What do implementations do?