Various changes to modernize the user interface of the Find, Replace, and Find in Files dialogs:

- Got rid of the "close" button, since it is redundant.
- Moved the buttons below the text fields, to make better use of screen real estate.
- Shorten the titles by getting rid of the "Dialog" part.
- Renamed "Search" title to "Find" to match the menu item.
- Renamed "Regular expression" label to the shorter "Regex"
- Added slightly more padding.
- Removed the "Replace+Find" and made "Replace" have this functionality. (all modern editors use Replace to mean "Replace and Find")

The attached png shows the before/after differences in the design of these dialogs.

I've made some minor updates: Adding colons to the labels and right-justifying them. These updates can be seen in the second comparison screenshot.

For illustration, attached idle_find_ttk.png, which is a minor layout tweak of the existing one (works on all the various find dialogs, though not shown in screen shot). I agree with Al's other suggestions here.

These changes all seem reasonable and have a nice look.
I have misgivings about shortening "regular expression" to "regex".
Otherwise, +1 for everything else.

Have attached find-dialogs.patch, which does some cosmetic tweaks to the existing dialogs, as per the previous screenshot. It uses ttk widgets if available, and standard Tk widgets if not.

Relies on the ui.py module (not attached, as it is changing often).

*Bump* Just wanted to bring attention to this issue. We could keep "Regular expression" instead of "Regex" for the label (Sublime Text and other editors have "Regular expression")

I think Mark's patch would be better over mine.

Al, thanks for the honest comparison. 

For 3.6, we can just import and use ttk with no fuss. 

When I get to this, I will review tests and responses to <Return> and <Escape> (see #27621).