improve build process

`devrv` build process should optionaly also remove some code, i.e console.log, console.debug.

source code => cleanup =>production code => minify

It should provide both js/jsm files :

```
CanvasUI.js                  - bundled production code
CanvasUI.min.js           - bundled minified production code
CanvasUI.debug.js       - bundled source code
```
