popup code should also try aligning right sides of drop down and around node

[bill]

If the around-node is on the right side of the screen, and the drop-down menu etc. is wider than the around node, the current code will fail because the default search path doesn't include TR: BR and BR: TR.

[bill]

(In [17413]) When aligning left sides of around node and drop-down causes drop-down to go off the right edge of the viewport, align left sides instead.

Also fixed RTL mode so that by default right sides are aligned.

Fixes #8948 !strict.

[bill]

(In [21108]) If ComboBox expands the drop down to match it's own width, it may need to adjust it's position too, so it doesn't fall off of the right side of the screen in RTL mode.

Fixes #10581, refs #8948, !strict.

[bill]

(In [21343]) Fix alignment of drop down for DateTextBox/TimeTextBox in RTL mode. Fixes #10676, refs #8948 !strict.

Could also move the marginBox() call (to set drop down width) before the call to dijit.popup.open(), but I've found setting a DOMNode size and then immediately querying the size to be unreliable on some browsers. (dijit.popup.open() queries the drop down size.)