Report when build in progress

https://app.asana.com/0/11331512503351/13274569624686

After merge add this line to jenkins shell command before `virtualenv -q $VENV` statement:
```
curl "http://localhost:3000/jenkins/pre_build?user=percolate&repo=hotlanta&sha=$GIT_COMMIT&status=pending&job=$JOB_NAME&build=$BUILD_NUMBER"
```
@jamesob we already have those:
![screen shot 2014-07-03 at 2 41 09 pm](https://cloud.githubusercontent.com/assets/122286/3474279/b5f7d6fc-02e1-11e4-8524-5769d48041c8.png)
And @malford told me it was complex to keep