Refactor/general improvements (#22)

* Micro optimization in function initializeNodes Graph/helper.jsx

* Improvements in Graph/helper.jsx

* Add version number on sandbox

* Aggregate some d3 constants in graph/index.jsx

* Add js md to method in Graph/helper.jsx

* Add unit tests to Utils.isDeepEqual to check for Array properties

* Add array support for Utils.merge function

* Update graph.test snapshot. Add package-lock.json

Author: danielcaldas

.gitignore

@@ -63,10 +63,11 @@ typings/
 
 # End of https://www.gitignore.io/api/node
 
-# PROJECT configurations
+# Project stuff
 dist
 lib
 coverage
 sandbox/rd3g.sandbox.bundle.js.map
 gen-docs
 .DS_Store
+**/.DS_Store