[QScintilla] tab stops and unified diffs

[Steve Borho]

Has anyone found a way to get tab stops to work correctly when
displaying diffs in a QScintilla widget?  The initial padding
character ('+', '-', or ' ') throws off the tab stop calculation by
one character and I've not found a workaround.

I've considered moving the + and - characters into a margin, but this
would break the diff syntax lexer.  If no one has any better ideas,
I'll probably resort to expand tabs to spaces in software, accounting
for the leading pad character myself.

-- 
Steve Borho