Fix unit tests not closing because application server process is still running

[LeNPaul]

See:

• mocha 4 doesn't exit unlike mocha 3 mochajs/mocha#3044
• https://boneskull.com/mocha-v4-nears-release/#mochawontforceexit

[LeNPaul]

For some reason, when letting chai-http create its own server application when it is running its tests, the server application does not automatically close. This might indicate that there is something in the server application code that is never gracefully closed (only forcefully closed even when it is running normally).

The solution right now is to point chai-http to a server application that is currently running on the server. The tests will finish and close since chai-http is not managing the server application (only making calls to the currently running server application), and the server application on the server will be closed separately like usual.