(dev) remove rewire, add babel-plugin-rewire. (#44)

* removed rewire. now using babel-rewire instead

* implemented more tests

* changed some eslint params

* linting

* linting

* coverage on getChant

Co-authored-by: Marcus Netz <marcus.netz@godyo.com>

functions/CountOccurences.js

@@ -1,5 +1,5 @@
 const CountOccurences = (arr, value) => {
-    return arr.filter((v) => (v === value)).length;
+    return arr.filter(v => v === value).length;
 };
 
-module.exports = { CountOccurences };
+module.exports = { CountOccurences };