fix the isNumeric and arrayEqual assert

The isNumeric parseFloat and arrayEqual logic in equal.js result in a bug that if an element's strokeWidth has been set, then animation on it won't work. Because +"0px" become NaN. 

And arrayEqual using == also won't work(match() returns an array，["px"] == "px" will result in false)

PS: 1st time pull request... forgive a newbee, just want to keep on with the new version.