Bukkit

Added /xfilter list.
Changed /xfilter addword and /xfilter removeword to /xfilter add and /xfilter remove, respectively.
Added more permissions.

- If a filtered word is used within another word it will block it. This is both good and bad, for example if I were to block 'word' then 'wording' would be '****ing' and 'expowordilicious' would return 'expo****ilicious'. In the first case it is good, you're blocking a usage of the word but in the second you're blocking its random occurrence in another word.