Provide a way to set an absolute dialog position, regardless of window size

[ripper234]

This happens on Chrome/Windows, although the issue seems to be generic.

See also on Stack Overflow:  http://stackoverflow.com/q/8485867/11236

Currently, if a dialog is given absolute position, it will not obey this position if the window is not large enough.

 http://jsbin.com/ifetag

Here is a fix suggested on Stack Overflow:  http://stackoverflow.com/a/8486190/11236 ( http://stackoverflow.com/a/8486190/11236)

[scott.gonzalez]

This is already possible in master.