_scrubJulian updated in setTimeFromBuffer for czml files

Signed-off-by: Ravi Agrawal <ravi.agrwl420@gmail.com>
_scrubJulian update moved up

Signed-off-by: Ravi Agrawal <ravi.agrwl420@gmail.com>
Extent.fromCartographicArray

The absense of this useful helper function became apparent during the International Space Apps Challenge.
Merge branch 'master' of https://github.com/AnalyticalGraphicsInc/cesium into timeline-scrubber
updateFromClock called inside setTimeFromBuffer
Fix to properly check for undefined values
Merge pull request #674 from macoda/timeline-scrubber

_scrubJulian updated in setTimeFromBuffer for czml files
Only set crossorigin on images that are actually cross-origin.

Cross-origin URLs are detected automatically by comparing the URL to the document location.
Fix formatting for define
Fix to properly check for 'undefined'
Fix to properly check for 'undefined' and default value initializations
Merge pull request #685 from AnalyticalGraphicsInc/smarterCrossOriginImages

Only set crossorigin on images that are actually cross-origin.
Fix to properly check for 'undefined'
Fix to properly check for 'undefined'
Fix to properly assign a default value
Fix to properly check for 'undefined'
Merge pull request #678 from AnalyticalGraphicsInc/extentFromCartographics

Extent.fromCartographicArray
Fix to properly check for 'undefined' and assign default values
Merge pull request #684 from andre-nunes/issue89

Fix to properly check for 'undefined'
Fix my botched pull request merge.