Added support for buttons and menuframes with rounded corners.

* Not turned on for default buttons and menuframes right now.
* Updated Deskcalc and Keymap to use buttons with rounded corners.
* Overloaded methods with radium parameters are not virtual right
  now so as to not break vtables. Added /*virtual*/ before each
  method that should be made virtual in ControlLook.h
* Added a light line to the left border of the down arrow frame
  on menu frames as a small visual tweak.
* Replace StrokeRect() with StrokeRoundRect() when drawing the
  default button indicator. This gives them a rounded
  appearance if the button is also rounded.
* Added protected methods _DrawMenuFieldBackgroundOutside and
  _DrawMenuFieldBackgroundInside.
* Created some protected methods to get the edge, frame, and bevel
  colors from a passed in base color because it was a mess and I
  needed to calculate the colors from mutiple methods. It is much
  cleaner now.
* Added myself to ControlLook.cpp authors list. Assigned copyright
  to Haiku, Inc. Stippi also retains his copyright.
* Tons of style fixes.
  - Change all instances of `if (flags & B_FLAG)` to
    `if ((flags & B_FLAG) != 0)`
  - Reorder some methods.
  - Reorder includes.
  - Spacing.
  - Updated comments.

src/apps/deskcalc/CalcView.cpp

@@ -419,10 +419,10 @@ CalcView::Draw(BRect updateRect)
 				flags |= BControlLook::B_IGNORE_OUTLINE;
 
 				be_control_look->DrawButtonFrame(this, frame, updateRect,
-					fBaseColor, fBaseColor, flags);
+					6.0f, fBaseColor, fBaseColor, flags);
 
 				be_control_look->DrawButtonBackground(this, frame, updateRect,
-					fBaseColor, flags);
+					6.0f, fBaseColor, flags);
 
 				be_control_look->DrawLabel(this, key->label, frame, updateRect,
 					fBaseColor, flags, BAlignment(B_ALIGN_HORIZONTAL_CENTER,