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.
- Remove keybindings from terrain dialog arrow buttons
- Fix arrow buttons not bound-checking fields
Dialog engine:
- Fix fields crashing after text is set while it has focus
- Trigger focus handler on untoast() to balance that in toast()
