Add flags to wrapper for message types about chatexchange

[banksJeremy]

I'm working on an Event class (which is what wrapper will expose; it will handle the JSON objects internally) which will have an enum (using the backported implementation of PEP-435 enums implemented in Python 3.4) class of those message types.

[Manishearth]

That would work :)

[banksJeremy]

5333ab8 successfully built in Travis using my credentials and using your credentials.

Since we already have an issue here keeping track of what's going on, including the above two CI builds, and I don't think it's necessary to create a distinct pull request. (edit: actually, I think I will at least this time, since that gives us a nice diff view that this does not)

Is it now fine for me to go ahead and merge stuff like this into master, without awaiting further discussion? Or should I just stage them into test but not go ahead with the final merge?

[Manishearth]

Yep :)