AttSwitch()
 Change screen attributes.
-------------------------------------------------------------------------------

 Syntax:

     AttSwitch( <cScreenImage>, <cNewAttribute> | <nBits>[, <cOldAttribute>] )
     --> <cNewScreenImage>

 Description:

     AttSwitch() will change ALL of the screen attributes in <cScreenImage>
     to <cNewAttribute> if <cOldAttribute> is NOT specified.

     OR

     AttSwitch() will change the screen attributes in <cScreenImage>
     which match <cOldAttribute> to <cNewAttribute> if <cOldAttribute> IS
     specified.

     OR

     AttSwitch() will change the screen attributes in <cScreenImage>
     which match <cOldAttribute> by <nBits> if <cOldAttribute> IS
     specified.

     OR

     AttSwitch() will change ALL of the screen attributes in <cScreenImage>
     by <nBits> if <cOldAttribute> is NOT specified.

 Returns:

     AttSwitch() returns a character string representing a new screen
     image.

 Note:

     If <cScreenImage> is passed by reference it will be changed directly
     by AttSwitch().


 Files:  Library is CUACLIP.LIB