TIMOB-14567 changed default color to black and add null value checking in propertyChanged method
TIMOB-14567 revert default color
Merge pull request #4498 from bijupmb/TIMOB-14567-ColorToNullOnLabelChangeToTransparent

TIMOB-14567 changed default color to black and add null value checking in propertyChanged method
Bug Fix
Merge branch 'master' of git://github.com/appcelerator/titanium_mobile into ios_windows_refactor
Modal Bug Fix
Default Image Stuff
Bug Fix