Gjn updateol newbuild

This PR

- updates to latest master of ol3 (https://github.com/openlayers/ol3/commit/ba060ccc502fb7c52edbb8eb159ca4db4d9e64ff)
- adapts the build to the new build system. As we don't want custom ol3 build for our api, we simply get rid of the exports files and use the @todo api notation to export the symbols we want.