The Preview is now the official API (no more view2D)

This PR removes the preview of the loader and makes it the official version that will be served. The examples and documentation inside mf-chsdi3 are adapted accordingly (mainly replacing View2D with View). Note however, that old simple code using View2D should still work (we use alias), but might break in other areas.

I've kept the old versions (old-ga.js and old-ga-whitespace.js) around to be able to switch back to the old version quickly. (Year-end and all...)

Once this is deployed, we need to adapt the API documentation hosted on github (-> https://github.com/geoadmin/ol3/pull/112) and also our examples in codepen.