removed 'isMac' check, annoying when testing context loss ;-)
reverted recent change of Starling's 'contextData' vs. 'customData' property (refs #218)

This caused more trouble than it's worth. The combination of allowing a shared context as well as automatically handling a context loss is difficult to balance.
using 'pixelPerfect' viewPort scaling only on iOS
Merge pull request #5 from PrimaryFeather/master

Updated from Primary Feather