move code out of reddit class (unix time stamp / web requests)

Web requests are now made in a separate class called "WebAgent", which should reduce coupling to the Reddit class.
Perhaps we could completely separate the execution of web requests from the object model? That should eliminate the need for creating and initializing web requests in different classes. Exception handling could also be simplified by adding a few error handling decorators. See https://github.com/raytheon/RedditFlat for an example.