R_MaxFnt()
 Determine number of INTERNAL (built-in) fonts
------------------------------------------------------------------------------

 Syntax
        nMaxFont := R_MaxFnt ()

 Parameters
        None

 Returns
        nMaxFont        Number of INTERNAL (built-in) fonts.
                        There are always the same number of EGA- and VGA
                        fonts available :
                        If R_MaxFnt() returns 2 means : there are 2 EGA
                        and also 2 VGA fonts available.

 Description
        Determines the number of INTERNAL (built-in) fonts.
        In the current version of RFntLib v1.0 there are 2 EGA and 2 VGA
        fonts available. This may vary in new releases of the library.

 Example
        *-- Number of available internal fonts
        LOCAL   nMaxFnt := R_MaxFnt ()
        LOCAL   nCnt
        *-- Array with font names
        LOCAL   aIntFnt := {}
        LOCAL   nChoice

        *-- Fill the array with the names of the INTERNAL EGA fonts
        FOR nCnt := 1 TO nMaxFnt
                AAdd ( aIntFnts, R_EGAName ( nCnt ) )
        NEXT
        *-- Let the user choose a INTERNAL EGA font
        nChoice := AChoice ( 8, 23, 8 + nMaxFnt - 1, 56, aIntFnts )

        [ ... ]