+ optional; if installed rbot can use localized messages
+ htmlentities http://htmlentities.rubyforge.org/
+ optional; if installed rbot will use it to decode
+ HTML entities; if missing, an internal table with
+ the most common HTML entities will be used instead
+ hpricot http://code.whytheluckystiff.net/hpricot/
+ optional, if installed rbot will used it to find
+ the first paragraph in HTML files; if missing,
+ regular expressions will be used instead
+