docs: revise resizing scripts to better organize the

tasks into chunks that are only executed when necessary.

Move the stuff that does the reference panel resizing
into a separate method because this should only happen when
literally resizing the panels. This thus resolves the problem
in which an invalid cookie would sometimes be written during
a normal window resize event -- there's no need to write that
cookie unless the user literally resizes the panel.

There's no need to call resizeWidth all the time, the doc-content
div can manage its width by inheritence and should only ever have
to resize its left margin when the side nav is manually resized or
when the page is loaded (in order to account for a saved side nav
width). This vastly improves the performance and visual quality
when resizing. However, IE6 still requires this in order for the scrollbars
to be visible in the content area. So a flag is now set when IE6 is
the browser, it has its own onresize method
and the width is defined only for IE6.

Inside resizeHeight, check what the href path is before doing any
resizing, just to make sure we don't do unecessary work and to
make the code more readable.