[[ Bugfix 11560 ]] Outer glow errors

Two errors existed in the distance transform function:

* Potential for overflow in radius comparisons
* Lines in the source image with no pixels had non-infinite x distance
Add bugfix note
[[ Bug 11571 ]] Update pixelScale after call to iphoneUseDeviceResolution
[[ Bugfix 11568 ]] Bitmap effect colors incorrect on iOS and Android.
[[ Bug 11571 ]] Add bugfix release note
Merge branch 'bugfix-11568' into release-6.5.1
Merge branch 'bugfix-11560' into release-6.5.1