LIMIT is applied to aggregated queries

[timbutler]

The default for a field type data query is to limit the results to 100. However, when the selector is changed to Aggregation, the limit still applies but the limit field is removed from view.

This means a query where you want to return a count of the entities, it will always be 100 if the numbers are greater than 100.

As I can see that the aggregation is Grafana / browser side, I'm not sure if the limit should be removed completely or at least displayed to allow an override.

[mariusoe]

Should be solved by PR #11