Simplify URL in `hubot help` output, add detailed URL to README.md

I've noticed some odd output when querying my hubot instance for help:

```
++
--
GET http:///shamu/scores[?name=][&direction=][&limit=&l...>]
[...]
```

The source of the third line above seems to be [line 16](https://github.com/ajacksified/hubot-plusplus/blob/master/src/plusplus.coffee#L16) of plusplus' documentation section, which I gather describes a method of looking up scores via web interface. It's hard to understand in this context, though, and (as you can see by the quoted text above) gets garbled by auto-linkifiers on services such as HipChat.

Is there a reason why that line is included in the `Commands:` section of Hubot's help docs? IMO this functionality would be better outlined in the `Description` section so as not to clutter the output of a `hubot help` query. This would also allow you to expound on its usage in a clearer and more comprehensive way.