* Updated gulp and its tasks.
* Updated three.js to the most recent compatible one.
* Use rollup to build the js module.
* Use google closure compiler to minify result of rollup and to add some type safety.
* Restructured project resources. we now build a working version into the dist directory.
* Introduced new javascript class syntax. Use import and export statements instead of goog.provide,e etc. methods.
* Some small fixes.