Adding JSX (React) as an option for the view engine in express

[Reshav-Paul]

The Express official docs list react as an option for the view engine using the express-react-views module.
This pull request adds jsx as an option for the view engine from the CLI using --view = jsx.

Commits have been made for -

1. Adding CLI support for jsx.
2. Default jsx templates
3. Tests to validate its working.
4. Updated README to include jsx

[Reshav-Paul]

Builds are failing on older versions of nodejs. It is passing fine otherwise.

[dougwilson]

Thank you! Do not worry about the failing older Node.js versions for this, as it does pass fine on the newer versions. I am adding a method to target a given Node.js version for the upcoming version, so this template would just fit in by requiring a minimum target version.

[Reshav-Paul]

That would be great! Thanks for the update.