Small doc fix
Fix and simplify the collection of anchors
Update the TOC *before* the file is written, not after

otherwise, Vim behaves strange
Removed unused functions; added a few more comments
Merge branch 'autocompletion' into dev
Moved non-escaped completion to my dev branch from autocompletion branch (authors refuse these functions in their branch)
Merge branch 'dev' of https://github.com/vimwiki/vimwiki into dev