convert PerformanceDisplay from canvas to div
update cesium viewer for changes
Merge branch 'master' into performanceDisplay
update style
update cesium viewer
update doc
Add support for a minimum level on OpenStreetMapImageryProvider
Update CHANGES.md
Check the number of tiles at the minimum level
Merge pull request #1409 from andre-nunes/minLevel

OpenStreetMapImageryProvider can now make use of minimum level
Minor tweaks to OSM imagery provider.
Merge pull request #1422 from AnalyticalGraphicsInc/minorOsmTweaks

Minor tweaks to OSM imagery provider.
Sanitize HTML by loading the official Google Caja sanitizer script in a Web Worker.

Users can sanitize in an offline environment by downloading the sanitizer script and overriding the default sanitizer property to use the local function.
Merge remote-tracking branch 'origin/master' into box-select
Caja is no longer included in the source tree.
Log a better message if the Caja script fails to load.
Avoid crashing when double-clicking a positionless object.
Remove hard-coded maximum height.
Fix specs now that sanitization is async.
Merge branch 'master' into performanceDisplay

Conflicts:
	CHANGES.md