Import highcharts.js .
Some more base code for statistics.
Replace highcharts.js with highstocks.js .

Highstocks has more features.
Now the charts use JSON to load the data.
Fix a bug for ajay requests.
Add database migration for table 'stats'.
Change chat type.
Add second graph.
Merge pull request #8 from ServerManager/feature/statistics

Merge feature/statistics.