Update ol

This PR updates OpenLayers in the project to the last ol3 master:
https://github.com/openlayers/ol3/commit/6276e633de061a819a50c30d1b48668628f792d6

I didn't need to change anything in mf-geoadmin3 because ol3 API have not changed (except for some projection stuff we don't use in mf-geoadmin3).

Please review and merge.