annotation count on hover in popup

Added counts of annotations for location popups. On mouse over you now see the number of annotation belonging to that specific location or timeseries.

Nothing is shown if you don't hover over the right line. This is to prevent server/hammering or sluggish response in the client

![location_count](https://cloud.githubusercontent.com/assets/160328/2601391/00973d44-bb0f-11e3-8009-3b5c12229361.png)
![timeseriecount](https://cloud.githubusercontent.com/assets/160328/2601392/0099b92a-bb0f-11e3-84b4-a5ffba4a859e.png)