Modify package.json version of express required.
Modify package.json version of express required.

Change version to existing install.

Verification:
Ran program as per params in previous commit 3c987589a714bcdad1caf2d1782399522f3caa49
Program still works with different version of npm

Reason for commit:
1. ran $ npm list in package directory; ERR npm missing express version (as per package.json)
2. cd home ~/
3. ran same $ npm list, no conflicts occurred
4. hence, must be a "global versus local" sort of npm conflict commonly seen

Solution:
changed package.json express version

abstractmachines/mean-stack-js-express-node-full-stack,abstractmachines/mean-stack-js-express-node-full-stack