Feature/express 4 migration

[robertcoopercode]

Issue

Fixes #140

Type

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

Now using Express 4.x instead of version 3.

Screenshots (if appropriate):

How Has This Been Tested?

• I have added tests to cover my changes.
• All new and existing tests passed.

---

This change is 

[robertcoopercode]

@vinitkumar I'll let you merge this into master.

[vinitkumar]

@Engineering-Robert Mostly looks great! One question though, did we needed to move server.js into app? I intentionally kept it outside as it has little to do with app code.

[vinitkumar]

Any reason to remove the render of 404 page on not found routes?

[robertcoopercode]

Ya, the 404 page was always being rendered when it was included in express.js, so I had to move it to the bottom of routes.js. I think it has to do with not using app.router (deprecated) anymore.

[vinitkumar]

Okay!

[robertcoopercode]

A lot of projects i've been looking at have their main server file in a "src" folder so I wanted to follow along with that practice by adding our server.js into the app folder. This way our root directory only contains dot files, READMEs, and other config stuff. Thoughts?