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
Fix bug in ol.structs.RBush#clear
Merge pull request #1415 from twpayne/rbush-clear

Fix bug in ol.structs.RBush#clear
Don't attempt to fit views to empty extents
Merge pull request #1426 from twpayne/view2d-fit-empty-extent

[master] Don't attempt to fit views to empty extents
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