Remove reference to Object.assign in the code
Remove reference to Object.assign in the code

The support for ES6 is preset from nodejs >= v4.0 (LTS) in order to preserve
backward compatibility with node v0.12 (LTS) and given its single use in
the code, line is changed to a basic assignation.

https://github.com/edina/eo-graph/issues/1

edina/eo-graph