Externalize code to separate include files to reduce memory consumption during normal site operation

I know I said (in release notes of beta1) that no additional features were planned, but there's something I would like to add, heh. I'll open a separate f.r.

Before than that though, I would like to split the code into separate scripts to reduce memory consumption during normal site operation. Our site runs more than 200 modules, and every bit helps.

Patch coming...