Mask:AddSay(R,C,Text): public: return true
  This window is appended by next Text for view in the R,C position relative
  to window beginning (i.e. to the left upper window corner).

  Parameter description:
  ~~~~~~~~~~~~~~~~~~~~~~~
  R: numeric: no default
   Position of edited data (row) relative to left upper window corner.

  C: numeric: no default
   Position of edited data (column) relative to left upper window corner.

  Text: character: no default
   The displayed text.