closes https://github.com/TryGhost/Ghost/issues/9543
- https://github.com/TryGhost/Ghost-Admin/pull/972 moved `keymaster` from Bower to NPM but version 1.6.3 is not published to NPM and it contains fixes for unbinding multiple keys (eg, `'down, j': 'moveDown'`). Switched to fetching directly from github to ensure we have the latest version
- removed the "has registered shortcuts" guard added in https://github.com/TryGhost/Ghost-Admin/pull/976 - it was working around the buggy keymaster version but was also buggy itself because it meant shortcuts could only be registered the first time a route was loaded even though we unregister all of the shortcuts when leaving the route
no issue
- keymaster bindings could be kept around between tests with references to objects that should have been deleted. This was manifesting itself with a Tags acceptance test failing because one of the key binding tests triggered two actions, one on the route under test and another on a route that was kept around from a previous Error Handling acceptance test (previous test intentionally had an aborted transition so the action in the current test was complaining about the first transition not being complete)
- add guard to ensure that shortcuts can't be registered multiple times on an object
- remove all `default` scope keymaster bindings when destroying a test app instance
no issue
- add eslint-plugin-ember, configure no-old-shims rule
- run `eslint --fix` on `app`, `lib`, `mirage`, and `tests` to move imports to the new module imports
- further cleanup of Ember globals usage
- remove event-dispatcher initializer now that `canDispatchToEventManager` is deprecated
no issue
- move all existing markdown editor behaviour out of the editor controller and isolate it into a single component that can be swapped out
- split the `register/remove` functions of the `shortcuts-route` out into a separate `shortcuts` mixin
