Word cloud for different languages

[MVsevolod]

This will be a nice feature to parse not only english, but also other languages for word cloud statistics.

[howardchung]

I think we restricted it because if we add e.g. chinese characters, the number of words goes way up and the word cloud loses a lot of meaning, so we currently filter to only words with [a-z] letters.

Maybe we could include cyrillic letters to allow languages like Russian, though.

[howardchung]

For reference this is the function converting a chat message line into words:
https://github.com/odota/core/blob/master/util/utility.js#L23