wonder who  resurrected a project after 8 years, impoting code from https://github.com/tag1consulting/forum2

- cosmetic changes

- link to last topic
- fixed missing last topic
- small bug fixed

- save user settings (number of topic, order)
- topic move and shadow works again
- block with active (last updated) topics
- previous/next topics in topic view
- checked that search works
- new permission to set whether a role's post is online or queued
- finished separation between html and code (theme_invoke)
- checked search
- cleanup, profiling, minor caching

- integration with taxonomy is more meaningful, as only one vocabulary is used to browse
- support for hierarchy, even multiple (subforums can appear in distinct forums)
- separation between code and html
- admin can choose some terms to be just "containers of other terms", and not of topics
- experimental caching of internal structures

(still some work to do, there are known bugs)