Nimbus L&F: 6u5-b06 skin file changes (Drivived Colors, Slider and Spinner Focus)

This is a round up of issues to be fixed in the skin xml file for 6u5-b06 which include:

Derived Colors - All colors in Nimbus should be derived from base colors in UiManager and they should reflect user changes to the colors in UIManager.

There is no focus painted on Slider and Spinner.

Nimbus L&F: JSpinner's down arrow button in pressed state shows up a white line below it.
Steps to reproduce:
1)Run SwingSet2, tab to the ColorChooser demo and then tab to the HSB tab in the color chooser dialog.
2)Press the down button of any of the 3 the spinners- Observe that there is a white line appearing below the spinner down arrow button.
Screen shot is attached for reference.

NimbusL&F: ColorChooser "Recent" gridCells are filled with Red color, instead of being empty by default.
This is observed on Nimbus L&F on all OSes, with the current 6u4b02 pit build.
Steps to reproduce:
1)Run SwingSet2 demo with Nimbus L&F and open the ColorChooser dialog in the Color Chooser demo tab.
2)Observe the grid cells are all filled with a red color, instead of being empty.

Button Gradients and Corner Roundness
The corners on JButton and JToggleButton are 2px more rounded than than the spec
The gradients for buttons don't have the mid points set as in the spec.
The gradient points for selected toggle buttons are not 100% vertical

Nimbus L&F:Active Inactive Internal JFrame look too similar.
This is observed on Nimbus L&F, on all OS, with the current 6u4b02 pit build.
Minimized JInternalFrame does not have an opaque background. Apart from the buttons(Maximize.Minimize,Restore) the rest of the minimized JIntFrame's shape is transparent and blends with the background.
Steps to reproduce:
1)Run SwingSet2 with the current 6u4b02 pit build and in the JInternalFrame demo, minimize the various JInternalFrames.
This is more clearly visible when you place the minimized JIntFrame over another Unminimized internal frame.

Nimbus L&F:Active Inactive Internal JFrame look too similar.
There are the following 3 bugs in the nimbus laf implementation: first, the text is left-aligned instead of center aligned; second; the text should be grayed out when "blurred"; third, the font is wrong.