- rename variables for URL template, use templateSrv to render URL links
- fix visibility of tooltip items and url template help popup whe the light theme is used
- rework Tooltip settings pane, organize tooltip editor fields
- rename properties in panel config, implement migration logic for legacy configuration
- close button for the frozen tooltip
- use relative positioning for proper page scrolling
- use babel to 7, update dependencies, fix#72
- proper babel build to support ngInject, fix#78
- proper buckets display in 6.3.0+, fix#76
- rename js to ts, build d3 lib as js, build src as ts
