Version 1.6

Version 1.6
Take into account changes made to the display margins, fringes and
scroll-bar handling.
(ruler-mode-margins-char): Removed.  Not used anymore.
(ruler-mode-pad-face, ruler-mode-fringes-face): New faces.
(ruler-mode-margins-face): New definition.  Moved.
(ruler-mode-left-fringe-cols)
(ruler-mode-right-fringe-cols)
(ruler-mode-left-scroll-bar-cols)
(ruler-mode-right-scroll-bar-cols): Reimplemented.  Moved.
(ruler-mode-full-window-width)
(ruler-mode-window-col): New functions.
(ruler-mode-mouse-set-left-margin)
(ruler-mode-mouse-set-right-margin)
(ruler-mode-mouse-add-tab-stop)
(ruler-mode-mouse-del-tab-stop): Reimplemented.
(ruler-mode-mouse-current-grab-object): Renamed to...
(ruler-mode-dragged-symbol): New.
(ruler-mode-mouse-grab-any-column): Use it.  Cleaned up.
(ruler-mode-mouse-drag-any-column): Likewise.
(ruler-mode-mouse-drag-any-column-iteration): Simplified.
(ruler-mode): Restore previous `header-line-format' if
`ruler-mode-header-line-format-old' has a local binding in current
buffer.
(ruler-mode-left-margin-help-echo)
(ruler-mode-right-margin-help-echo): Removed.
(ruler-mode-margin-help-echo)
(ruler-mode-fringe-help-echo): New constants.
(ruler-mode-ruler): Use them.  Reimplemented.