instead of over and over. Typical speedup is ~4x. Max possible speedup:

  instead of over and over. Typical speedup is ~4x. Max possible speedup:
  8x.
* Add "scan" parameter to hook(), which is used to make the hook be called
  during the scanning pass, as well as the render pass. The meta and tag
  plugins need to use the new scan parameter, so will any others that modify
  %links.
* Now that links are calculated in a separate pass, it can also
  precalculate backlinks in one pass, which is O(N^2) instead of the
  previous code that was O(N^3). A very nice speedup for wikis with lots
  (thousands) of pages.