* [feat] Feature flag system via config
Adding a feature flag system that is driven by superset_config.py. This change includes:
- Server side changes to specify a dedicated FEATURE_FLAG dictionary for listing feature flags. E.g.
```
FEATURE_FLAGS = { 'SCOPED_FILTER': true }
```
- Pass the new feature flags to client via bootstrap-data
- Client side changes to inject feature flags into the redux state tree for dashboard, explore view and SqlLab
- Client side refactor/clean up so the feature flags can be properly tested. Also avoid modifying incoming bootstrap data when creating initial state for the redux state tree
- Re-enable tests that were previously disabled for ExploreViewContainer
* Fix lint errors.
* Remove the partial attempt to get reference to src working in tests (so we don't have to write ../../../src and such in tests). This will in a separate PR.
* [toasts] get rid of notify globals, refactor messageToasts for use by entire app
* [remove notify] use arrow func in ajax call
* fix lint + tests
* actually fix tests from messageToast refactor
* add 'test:one' npm script
* debugger
* [toasts] convert bootstrap flash messages to toasts in explore + sqllab
* [toasts][tests] import from right file
* Change in files
* Renamin files and folders
* cleaning up a single piece of lint
* Removing boat picture from docs
* add superset word mark
* Update rename note in docs
* Fixing images
* Pinning datatables
* Fixing issues with mapbox-gl
* Forgot to rename one file
* Linting
* v0.13.0
* adding pyyaml to dev-reqs
