twCreateButton( wT, wL, cButton, lPad, wColor, wSType )
 ----------------------------------------------------------------------------
     Create a half height, half width shadow around a string in a
     window area.

       Arguments:

     wT, wL  - 'N' Relative Window Coordinates

     cButton - 'C' String to put on the button

     lPad    - 'L' Logical to pad the button with a space on both ends.

     wColor  - 'C' Clipper colour attribute. Defaults to current window
                   color.

     wSType  - 'N' TSDWIN Shadow Type. Defaults to current shadow type.

       Return:

     NIL

       Example:

     twCreateButton( 5, 5, "Trial Button", .T., "w+/rb" )