Activity -> Useractivity to avoid db init errors during testing
Added chart and observation validation and ranking API
Merge branch 'feature/visualisations' of codebasehq.com:playgen/celar/datacon into feature/visualisations
Function to add (or increment count if already added) search term to terms table
Added method to get main (most frequent) date for each table for use in search
Merge branch 'feature/angular' into feature/visualisations