[Bf-committers] UI changes from cycles branch

[Micael]

@Brecht, I like it better now, still:

- As Αντώνης suggested, the panel titles should be more discerned. I would
put just a little more contrast in the emboss effect of the title "box"
and/or darken the background.

- On the dropdown menus, it is my opinion that the arrows should be of a
light color instead of a dark color. But it's now visible enough not to be
accidentally missed.

Anyway, great work!

-- 
Micael Dias