Set the video mode
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 Syntax

        GT_VideoMode( nRows , nCols )

 Arguments:

      nRows - Number of screen rows
      nCols - Number of screen cols

 Returns:

      .T. if successful
      .F. if failed

 Description:

      The video mode is set to nRows * nCols.  If this fails, the mode should
      not change.

      The following constants are currently available :

      Rows                Columns
      V_EGA       43      V_SINGLE    80
      V_VGA       50      V_DOUBLE    40
      V_NORMAL    25      V_NOCHANGE  0


 Examples:



 Source: VIDEOMOD.PRG

 Author:  Martin Colloby