The HSV-to-RGB function had been returning values in the range [0,1].
Now it uses [0,255] to be consistent with the other values returned by
_getColor.
It turns out that `window.native.someMethod` always evaluates as
`undefined` -- even if calling that method would succeed. This change
removes checks for such methods so that the WeDo2 blocks can work.
Note that the hat blocks are still unimplemented, and some assumptions
are made about the form that arguments and `util` will take.
