Behaviorally: This change makes it so that Enter will never cancel
a dialog, unless that dialog only contains info to be read. Escape
will never unpredictably be treated as Enter. And some dialogs without
Escape to cancel, now can be canceled with Escape.
A lot of this just refactors dialogs to define the cancel button
at the top, not as a hotkey on a cancel button deep in the XML.
I think this makes enter/escape behavior in dialogxml files more
legible at a glance.
In effect, this is a combination of two of the previous pickers:
the location picker, and the editable string picker.
This required quite a significant rework of how the tilemap places its children.
Currently it's only used in special node editing.
I plan to add its use in many other places too though.
