feat(elasticsearch): began work on elasticsearch datasource, based on work in pr #2293, will need a lot more work

Iterate over the right env override list variable

fix(inspector): lots of improvements and fixes for the error inspector, now shows you request details and responses in many more cases, fixes #2646

fix(influxdb): fixes and refactorings of influxdb 0.9 editor, no longer shows template vars in keys dropdown and group by dropdownm, fixes #2636

influxdb doc: typo fixed

fix(graph tooltip): multi series tooltip did no highlight correct point when stacking was enabled and series were of different resolution, fixes #2620