Seek position modes

• start - Seek from start of the stream/file
• current - Seek from current position
• end - Seek from the end of stream/file

enum Efl.Io.Positioner_Whence {
    start: 0,
    current,
    end
}

typedef enum {
    EFL_IO_POSITIONER_WHENCE_START = 0,
    EFL_IO_POSITIONER_WHENCE_CURRENT,
    EFL_IO_POSITIONER_WHENCE_END
} Efl_Io_Positioner_Whence;