* Undo fix for #3585 since it has broken the stacked bar charts when the axis has a user defined minimum value.
* When a value of 0 is requested for a vertical logarithmic axis, return the bottom point
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.
gridLines.circular is a new option that toggles circular lines. This allows radar charts with circular lines #3082
pointLabels.display is a new option that toggles the display of point labels.
The existing angleLines.display is used with the new pointLabels.display setting is used to trigger the radar like settings.
This required changing the default polar area config.
In order to take full advantage of the new plugin hooks called before and after a dataset is drawn, all drawing operations must happen on stable meta data, so make sure that transitions are performed before.
Fix bar draw issue.
1. `Chart.elements.Rectangle.draw` function supports both horizontal and vertical bar.
2. Corrected bar position at minus.
3. Adjust bar size when `borderWidth` is set.
4. Adjust bar size when `borderSkipped` is set.
5. Adjust `borderWidth` with value near 0(base).
6. Update test.
In order to simulate real-time chart updates (i.e. horizontal animation), it's necessary to distinguish a removed or added value from a simple update. The dataset controller now hooks array methods that alter the data array length to synchronize metadata accordingly. Also remove the duplicate calls of updateBezierControlPoints() for line and radar charts.
Now that the aspect ratio is correctly handled, fix samples for charts with aspect ratio of 1 which was vertically too large. Also fix the default aspect ratio for radar charts which wasn't applied when creating a chart directly using new Chart(ctx, { type: 'radar' }).
Fixes a rendering issue when there are multiple datasets on a pie chart and they do not all contain the same number of data in their datasets
Fixes#3309
Change the linter in gulp tasks to be consistent with Code Climate results which are based on ESLint using .eslintrc options. However, defaults Code Climate rules are too strict, so turn as warnings the 'complexity' and 'max-statements' rules (other errors has been fixed). Note that the Gulp task name has been changed for `gulp lint`.
