NNUI: Text boxes should have focus

[acerspyro]

Currently in NNUI (latest master at the time of writing), the interface seems to be hover-based rather than focus-based.

This means that you have to keep your mouse cursor inside the text box to keep typing. In a focus-based approach, clicking the text box would give it focus, and anything you input will be typed inside of the text box. Pressing Enter would keep your changes and take the focus away from the text box, while pressing Escape would cancel all changes and take the focus away from the textbox.

I find it rather annoying to have to keep my mouse cursor in the text box areas to be able to type in them, and it could very well confuse new players.

[qreeves]

I did sort-of fix this with the previous "textedit" stuff linked to the old UI, but NNUI handles this differently and I haven't found an adequate vector for overriding this yet. It bothers me as well, so it will be fixed before I pronounce NNUI "complete".

[Norakam]