Update documentation on testing with Cypress

[crisner]

Fixes #433 (<=== Add issue number here)

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[jywarren]

Fantastic!!!! 🎉

[sagarpreet-chadha]

Also we can run cypress tests in headless mode, we should add that to documentation as well, because not everyone will want to open separate server for running cypress tests 😄

[sagarpreet-chadha]

As a follow up, let' combine these 2 commands into one command:
npm run cypress which will be equal to npm run start && npm run cy:run:chrome in package.json. Thanks!
Can be a FTO a well!

[crisner]

Awesome! I'll create an FTO for this.

[crisner]

Also we can run cypress tests in headless mode, we should add that to documentation as well, because not everyone will want to open separate server for running cypress tests 😄

Unfortunately, running Cypress tests in headless mode doesn't seem to work in these tests. Tried initially when I was setting up the tests to run in Travis. I am assuming it is because a child window is used. I had to incorporate the use of a child window as the default window did not like any change in the hash.