Fix java.lang.ClassCastException in requestAnimationFrame
Merge pull request #30 from mseddon/r-a-f-unbreak

Fix java.lang.ClassCastException in requestAnimationFrame
Change TextMetrics.width to be Double
Merge pull request #31 from mseddon/textmetrics-not-int

Change TextMetrics.width to be Double
Update README.md
Upgrade to Scala.js 0.5.0-RC2.