Update to Vue-CLI 4

Changes:

• Updated from Vue-CLI 3 to Vue-CLI 4
• Also updated all other dependencies including NW.js
• Simplify ESLint config
• Add automated lint/testing with Travis
• Added an example of accessing the File System from a component (or using require for any module)
• 100% Jest test coverage maintained
• Add some Linux specific stuff to the package-lock

Diff since last release:

• v1.0.0...v1.1.0

Missing features:

• E2E Testing (accepting PRs)

Initial release

I thought I had already done a release of this, but I guess not. This release is fully production ready (as long as you don't need E2E).

Main features:

• npm install && npm start works for local development inside NW.js
• 100% Vue-CLI compatible. Works just like a normal Vue CLI project
• Automated builds for each OS
• 100% Unit Test Coverage
• ESLint set up

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Missing features:

• E2E Testing (accepting PRs)