now use CSS style to get colors for rendering. Checkboxes also use the CSS border rendering
code. Added New utility methods to nsFormControlFrame to PaintCircular backgrounds and
borders. Set compiler directive to gfx-render radiobuttons and checkboxes both for printing
and on-screen display.
Created nsFormControlHelper::GetBool and nsFormControlHelper::GetBoolString
utility methods for converting strings into booleans and vice versa.
Modified nsCheckboxControlFrame, nsRadioControlFrame, and nsSelectControlFrame
to use these helpers.