Fixed eldoc behavior.

Fixed eldoc behavior.

      * python-eldoc-setup-code: The code to get help now uses the
        inspect element. When an object doesn't have documentation and
        if it is callable it returns the signature for it. Also when
        an object does contain documentation it only returns the first
        line.

      * python-eldoc-at-point: has been simplified to just message the
        doc header of objects.

      * python-info-current-defun: was not taking into account the
        current indentation so point was always inside a defun, even
        if the indentation was less or equal than the defun above.