Hipchat adapter + Boltdb store

Hi, we've recently started using Victor to power our company chat bot and I've made a few additions with a few more in the pipeline. Our old bot was node.js but I'm learning go and this is a great excuse. 

Speaking of which, I've only been writing go for about a week. This code works for us but I can't vouch for it's purity or adherence to idiomatic go and I'm happy to make changes as needed.

This pull request includes a chat adapter for [Hipchat](https://github.com/abachman/hipchat-go) and a store adapter for [boltdb](https://github.com/boltdb/bolt).
Yes, I can pull it apart. 

I made greedy a thing because I noticed that even with ordering the function definitions differently, iterating over the map would sometimes trigger the wildcard before other, more fully specified handlers, probably because of [the unpredictability of map iterations](https://blog.golang.org/go-maps-in-action#TOC_7.).