Compare new setRotationCenter values after truncating to 32bit
Compare new setRotationCenter values after truncating to 32bit

`Skin._rotationCenter` is a twgl vector or said another way a
Float32Array. JavaScript casts values stored in this array as 32 bit
floats instead of JavaScript's standard 64 bit floats. Comparing the
equality, like `setRotationCenter` does, of a 64 bit float against a
value stored in a 32 bit container will virtually always be false.
Truncating the new value into a 32 bit (losing precision) will give a
more useful comparison and remove a lot of current false positives.

LLK/scratch-render,LLK/scratch-render