Upgraded to Rails 2.0.2, except that we maintain
vendor/rails/actionpack/lib/action_controller/routing.rb
from Rail 1.2.6 (at least for now), so that Routes don't change. We still
get to enjoy Rails's many new features.
Also fixed a bug in Chunk-handling: disable WikiWord processing in tags (for real this time).
Fixed a bug in the HTML5lib tokenizer (affects S5 slideshows).
Some miscellaneous code cleanup. In particular, don't bother with zapping control characters;
instead, rely on is_utf8? method to raise an exception (which we do anyway).
