I intend to install the attached patch in the next days.  Its main
purpose is to allow pixelwise resizing of frames and windows.  In order
to resize frames pixelwise use the option `frame-resize-pixelwise'.  In
order to resize windows pixelwise customize `window-resize-pixelwise'.

In addition, you can use dividers between windows which can be activated
by customizing the frame parameters `right-divider-width' and
`bottom-divider-width'.  The patch should also remove gaps between side
by side windows and the necessity of extending the fringe of the
rightmost window.  Finally, functions like `fit-window-to-buffer' and
`fit-frame-to-buffer' will use the size of displayed text to resize
windows and frames accurately.

I tested the changes on Windows XP and GNU/Linux Debian 7.0.  I did not
test them on OS X since I do not have access to such a machine.  Likely,
Emacs will crash or simply fail to compile on such systems.  I'd greatly
appreciate if someone could help me testing and fixing that.

Thanks for your attention, martin