Fixes "Could not find image named" errors

Switchting the IB files to Xcode 5 introduced some kind of image reference for some of our popup buttons, which was kept when we switched back to 4.6 format.
However as this wasn't used in the 4.6 files before switchting to 5 either, I just removed that stuff.
Fix "Invalid color System, labelColor" error

At some point Xcode decided to introduce a new variant of black named "labelColor" (which is 10.10 only). This commit changes the DBView xib back to controlTextColor instead.