* Add support for description in fixtures
* Update datasetController to draw active(s) last
* Handle hiding of line by borderWidth
* Disable filling of scatter charts by default
* Make radar chart consistent with line
`controllers.*.js` and `core.datasetController.js` are now importable (no more function export), that's why there is so many changes mainly due to one indentation level removed. Split code for `bar/horizontalBar` and `doughnut/pie` in separate files, added a global controllers import (`src/controllers/index.js`) and add tests to check that all dataset controllers are correctly registered under `chart.controllers.{type}`.
JSON doesn't support functions which are needed to create scriptable options, so implement a very basic method to load a JavaScript file exporting the config in `module.exports`. Also rename test sources (remove the `jasmine.` prefix), cleanup `karma.conf.js` and add an example .js fixture config (bubble radius option).
Replace the old style canvas "mock" context checks by image based unit tests which are easier to maintain and allow more flexibility in the drawing logic since we are not testing the context calls but the final painted result.
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.
`karma.conf.ci.js` has been merged into `karma.conf.js` for local testing consistency: `gulp unittestWatch` has been replaced by `gulp unittest --watch` and thus use exactly the same config file. Upgrade to latest jasmine and karma packages and remove deprecated `gulp-karma` dependency (directly use `karma.Server` in gulp).
Split `test/mockContext.js` into smaller `test/jasmine.*` modules to make easier unit tests maintenance and finally, move all `*.test.js` files under the `test/specs` folder.
