Fix combo box and date field small & large styles box-shadow on focus (Valo)

Don’t override any other state than the “normal” for large & small
styles (box-shadow in particular)

Change-Id: I295b5e2300a4b2137171fb0aa55d5bbf3feb8cf6
Make custom panel caption styles better looking (Valo)

If the background color of the caption is darker than the normal
background color, add a colored border around the whole caption.
Otherwise only draw the bottom border using the default background
color.

Fix caption bevel and “well” style box shadow handling as well.

Change-Id: I1964df984ba50da8fcd1eed48edeb89abc5d3d8c