Add model ThresholdValue
Move measurements to patient as a detail_route
Refactor graph serialization
Implement lower and upper threshold value series in graph_data
Test graph data endpoint
Fix whitespace
Update or create threshold value in patient partial_update
Remove max and min thresholds from patient model
Update measurements endpoint of current patient
Test current patient graph data endpoint
Merge pull request #57 from sigurdsa/threshold-value

Multiple threshold values