exports needed for feature & vectorlayer by mapstraction

Please can we have these 4 exports incorporated so that mapstraction can work with the compiled ol.js file. The latest mxn ol3 implementation is currently here: https://github.com/mapstraction/mxn/blob/release-3.0-tile-layers/source/mxn.openlayersv3.core.js

If you have any suggestions to improve it that would be good too!