code optimizations for core functions

[Uranium235]

First off, I am sorry to post this as a bug.

But I am not familiar with bazaar (go git!) to branch and request a merge, so I hope I am forgiven.

While I had a closer look at the code for determining seo and file names (for a fix to the seo module), I had a hard time understanding what was going on.
In the end I think I got it and was amazed... no disrespect, but that is a good example of how to solve an easy problem the hard way, imho.

I attached a patch for functions.all.php making things a lot more readable, with added performance benefit.
I also included functions.modules.php where I removed some obsolete code.
I modified the index.php to return 404 status codes instead of redirecting to the homepage in case of failure. I think that is the proper way to do it, not the least to help search engines remove faulty links from the index.

[Uranium235 (uranium235)]

Removed the attached patch. All changes and other bug fixes are now in the branch lp:~uranium235/pluck-cms/pluck-cms