Issue: pthreads

PHP provides access to multi-threading via the pthreads extension: http://docs.php.net/manual/en/intro.pthreads.php

The speed of VaultWiki can be dramatically improved by using multi-threading to handle various tasks like constructing the sidebar, preparing various components (text, categories, etc), and even parsing multiple comments at once.

This is potentially a major change, so full pthreads support should not be implemented until 4.1.