[PATCH] [analyzer][Review request] Improved checker lists.

[Jordan Rose]

I committed most of this for you in r207478, just to split it up. (Sorry if that was presumptuous.) Among the modifications I made were replacing the `<div class="separator"></div>` with slightly cleverer CSS, tweaking the ZeroAllocDereference checker to have an example that wasn't just a bounds check, making the categories slightly clearer, and commenting out undefbehavior.DeadReferenced.

Why the last one? Because a lot of the examples didn't show uses of the //previous// object, but rather uses of the new object that might //look// like uses of the previous object. I didn't want to spend all of our time cleaning it up before getting the rest of the improvements in, though, so I just hid it inside a comment for now.

I also dropped the link from checker_dev_manual.html because implicit_checks.html doesn't seem to exist. What was that change intended to do?

http://reviews.llvm.org/D3457