Remove d3 from dependencies.  Usin CDN
Setup new sensor data callbacks
updating
updating
updating
Fix bridge and event_loop. Log events to database.
Merge pull request #57 from andyweaver/clean_bridge_output

Clean bridge output
Close db.session for each web request.
Move graph code into get_sensor_data callback and add CSS
Merge pull request #58 from reillysiemens/dev

Close db.session for each web request.
Add spacing and transition to bars
Merge pull request #59 from kyle-rader/use-d3

Use d3