separated TOC from page

This patch introduces a tpl_toc() function which can be used to freely place
the Table of Contents in a template. When used, tpl_content should be called
with a parameter of false to supress the automatic TOC placement.

Note: if tpl_toc() us run *before* tpl_content(), TOCs will not work in the
preview. A work around is to run tpl_content() in a output buffer first.

This patch also adds a getTOC() function for admin plugins which allows plugin
authors to put create their own TOC which will be placed correctly in the
template. A convenience function html_mktocitem() is available.

The config manager was adjusted to make ue of this new feature, but some bugs
might remain.

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