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.
New `options.resolve` helper that determines the final value to use from an array of input values (fallback) and a given context and/or index. For now, only the bubble chart support scriptable options, see documentation for details.
Add scriptable options documentation and update the bubble chart dataset properties table with their scriptable and indexable capabilities and default values. Also move point style description under the element configuration section.
`karma.conf.ci.js` has been merged into `karma.conf.js` for local testing consistency: `gulp unittestWatch` has been replaced by `gulp unittest --watch` and thus use exactly the same config file.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.
