Replace es6-shim, es6-promise and reflect-metadata with core-js, because it coveres all required dependencies / shims in one single dependency / library.
Closes#477.
* build: separate demo-app in its own directory.
* chore: replace gulp-inline-resources with a script
This also improves upon the relative path problem. All template paths
now should be relative. Also, we can now include double-quotes in
CSS/HTML.
Hans