Way for new Mac touch bar to behave the same as the Old keyboard
In the system preferences go to "Keyboard". Select the "Shortcuts"-tab. Select "Function Keys" in the left menu. Click the + and add the applications where you want the F-keys to always show.

If you never want the touch bar but the old F-keys with brightness, volume backlight and so on. Go back to the "Keybard"-tab and select "Expanded Control Strip" in the "Touch Bar Shows" drop-down menu.