meld scrollbars

[Stephen Kennedy <stevek gnome org>]

Hi all, if anybody has been using the svn version, you'll have noticed
that the margin drawing has moved into the scrollbar trough. I don't
think the change has been entirely successful and plan to revert it.
Pros and cons:
+ All textviews now get a diff map (previously the middle pane
wouldn't have one)
+ The textviews get a little wider
-  Scrollbar gets very busy looking - with many changes the scroll
handle is obscured

Another option is to remove the scrollbars from the textviews entirely
and have one master scrollbar for all panes with a combined diffmap
beside the scrollbar.
+ Middle pane gets a diffmap
+ Saves some horizontal space
+ No scrollbars mean prettier drawing for 3 way merges
+ Does anybody use the other (non right hand side) scrollbars anyway?
I only use them when a large block has been deleted and want to look
at the contents.

I did some experiments with this option but didn't get very far as I
couldn't find the magic to turn off the vertical scrollbar and hook it
up to an external scrollbar. Any links to gtk scrolling docs welcome.

Comments?
Stephen.