Removed useless doc.
Add Zoomify stuff
Bad doc param.
Removed direct access to private image_ property (warnings in build.py)
Merge branch 'zoomify' of https://github.com/oterral/ol3 into zoomify

Conflicts:
	examples/zoomify.js
	src/objectliterals.jsdoc
	src/ol/source/zoomifysource.js
	src/ol/tilegrid/zoomifytilegrid.js