* Support code hot reloading for JavaScript projects
* Add some missing JavaScript symbols and APIs
* fix the Travis build
* (review changes) remove the js type from the standard library as it doesn't follow NEP-1
* more additions to the DOM module
* Follow NEP-1 in jsffi; spell 'hot code reloading' correctly
* introduce a jscore module
* Document jscore module.
* readded js type
* Remove the '$' operator that doesn't behave
