Unify all the contents pages
Re-arrange TOC for better organization
flesh out last section of TOC
Expand core-libraries section out

Also add global constants and functions to last section
alphabetize sessions page
Remove core-libraries/router.rst

It is fleshed out in development/routing.rst
unify all TOCs across languages
Remove unused router.rst
Add a requirements.txt file

This format is used by many virtualenv wrappers to setup python requirements.
remove unlinked files
remove one more reference to core-libraries/router
Remove duplicate dispatch-filters entry
Add server-% make target to help serve a language to a browser
unlink security from "Utility Classes"

It is now duplicated under the "Security" page of "General Topics"
Make sidebar title readable
link to part-two of the bookmarks tutorial
Add hack to force displaying section headers on the sidebar

If the sidebar ever changes in size, we'll need to modify these magic numbers :(
Remove unlinked core-libraries.rst
Merge pull request #1889 from cakephp/3.0-better-toc

3.0 better toc