The `fill` option now accepts the index of the target dataset (number) or a string starting by "+" or "-" followed by a number representing the dataset index relative to the current one (e.g. `fill: "-2"` on dataset at index 3 will fill to dataset at index 1). It's also possible to "propagate" the filling to the target of an hidden dataset (`options.plugins.filler.propagate`). Fill boundaries `zero`, `top` and `bottom` have been deprecated and replaced by `origin`, `start` and `end`.
Implementation has been moved out of the line element into a new plugin (`src/plugins/plugin.filler.js`) and does not rely anymore on the deprecated model `scaleTop`, `scaleBottom` and `scaleZero` values. Drawing Bézier splines has been refactored in the canvas helpers (note that `Chart.helpers.canvas` is now an alias of `Chart.canvasHelpers`).
Add 3 new examples and extend utils with a pseudo-random number generator that can be initialized with `srand`. That makes possible to design examples starting always with the same initial data.
Move base platform definition and logic in src/platform/platform.js and simplify the browser -> Chart.js event mapping by listing only different naming then fallback to the native type.
Replace `createEvent` by `add/removeEventListener` methods which dispatch Chart.js IEvent objects instead of native events. Move `add/removeResizeListener` implementation into the DOM platform which is now accessible via `platform.add/removeEventListener(chart, 'resize', listener)`.
Finally, remove `bindEvent` and `unbindEvent` from the helpers since the implementation is specific to the chart controller (and should be private).
Refactoring to put browser specific code in a new class, BrowserPlatform.
BrowserPlatform implements IPlatform. Chart.Platform is the constructor for the platform object that is attached to the chart instance.
Plugins are notified about the event using the `onEvent` call. The legend plugin was converted to use onEvent instead of the older private `handleEvent` method.
Wrote test to check that plugins are notified about events
Plugins can now be declared in the chart `config.plugins` array and will only be applied to the associated chart(s), after the globally registered plugins. Plugin specific options are now scoped under the `config.options.plugins` options. Hooks now receive the chart instance as first argument and the plugin options as last argument.
Rename `Chart.pluginService` to `Chart.plugins` (so move the old Chart.plugins array as a private member of the service), and rename `notifyPlugins` to `notify` for consistency with other service methods.
Data controllers should now rarely implement addElements and addElementAndReset but instead should define dataElementType (and optionally datasetElementType). Also remove some dead code (e.g. numBars, colorForNewElement, etc.).
