yarn.lock files are generated for embark and embark-ui, and their package.json
files and other npm related files are updated to support and require using yarn
for development of embark itself and for embark's CI.
Allow for embark sources to be authored in TypeScript and/or JavaScript, and to
make use of upcoming features of the JS language. Sources in the src/ directory
are transpiled into the dist/ directory, and npm-scripts are provided to
support and automate various aspect of the build process. Source map support is
enabled at runtime, i.e. when invoking the embark cli and running embark's test
suite.