Order of Latest 311 Items

Hi Guys,
Just looking at the code for the first time! It looks great, easy to read and understand.

I did notice what looks like a bug in the `latest_311_intent`. I'm not 100% sure but I don't think the "latest" 311 issues are being returned by the app.

An easy fix to this would be to change from datastore_search to datastore_search_sql as is being done in the crime_activity_intent.

Then use an ORDER BY on the SQL query on the method get_raw_311_reports_json in latest_311_intent.py line 75 will fix this.
```
'''SELECT * FROM "{}" ORDER BY "open_dt" DESC LIMIT {}'''
```