Feature/v3 (#225)

* Remove Vue dependency and change extends

Signed-off-by: Jakub Juszczak <netghost03@gmail.com>

* 💎 Release new version 3.0.0-rc0

* ⬆️ Update examples

* 📝 Update README.md

* ⬆️ Update examples

* ⬆️ Update englishd docs

* ⬆️ Update transalted docs with current code examples

* 🔥 Remove dist files from gitignore

* ⬆️ Update dependencies vue and chartjs

* Change private data

Implements #182. The private chart instance is now in the vue.js data model. And can be accessed over `this.$data._chart`
Updated unit tests

* 📝 Update docs with private data

* ✨ Add codeclimate ignore

* ⬆️ Update codeclimate

* ⬆️ Update codeclimate

* ⬆️ Update codeclimate

Add build and config folders to ignore

test/unit/specs/PolarArea.spec.js

@@ -51,13 +51,13 @@ describe('PolarChart', () => {
       components: { PolarChart }
     }).$mount(el)
 
-    expect(vm.$children[0]._chart.chart.ctx).not.to.be.null
+    expect(vm.$children[0].$data._chart.chart.ctx).not.to.be.null
 
     vm.$destroy()
 
     vm.$nextTick(() => {
       vm.$forceUpdate()
-      expect(vm.$children[0]._chart.chart.ctx).to.be.null
+      expect(vm.$children[0].$data._chart.chart.ctx).to.be.null
       done()
     })
   })