Show if a pull request can't be auto-merged

If a pull request can't be auto-merged display that where the status
would otherwise be shown.

Also as it now has commit comment counts in the info add that 
number to the number of comments on the pull request so you get a 
better picture of activity on the pull request.

Inability to auto-merge looks like this:

![screen shot 2014-07-04 at 16 29 37](https://cloud.githubusercontent.com/assets/35035/3483644/c4d8cf1c-0392-11e4-8ff8-7d802bf32b21.png)