Fix: prevent crash of iOS app on /api/user calls

v1.0.2, Fix: prevent crash of iOS app on /api/user calls

And also:

• testing: faster and more robust automated tests
• safety: throw error in mongodb init, if any
• refacto: whydJS to init the database automatically at startup

v1.0.1, Fix playemjs bug #74 (youtube id starting with -)

And also:

• automatically install/update playems on npm i
• upgraded node.js from 6.6 to 6.11.1, following security update
• improved setup instructions