Add Zoomify stuff
Resize bad tiles + changed demo image (due to crossorigin problems)
Remove extra tiles.
Export ol.proj.Units.PIXELS
Update ol.source.Zoomify to use new exports system
Update ol.tilegrid.Zoomify to use new exports system
No need to use private variables in ol.source.Zoomify
Make options to ol.tilegrid.Zoomify optional
Don't check examples with PhantomJS that begin with // NOCHECK
Don't attempt to check Zoomify example with PhantomJS
Export ol.proj.Projection#getUnits

Fixes #1365
Merge pull request #1438 from fredj/proj-export-getUits

Export ol.proj.Projection#getUnits
Make build.py compatible with Python 2.6
Merge pull request #1447 from probins/build

Make build.py compatible with Python 2.6
Make ol.source.TileImage#tileCache protected, not private
Make ol.source.TileImage#crossOrigin protected, not private
Make ol.source.TileImage#tileLoadFunction protected, not private
Refactor ol.source.Zoomify to use a private tile class
Remove unused variable
Tidy up ol.source.Zoomify tile grid calculations