Re-defining range node to scale

@knolleary, @dceejay , here's my intended change to the "range" node. I'd rename it as "scale". I also extended the HTML docs and added the first two sample unit tests.

If you're happy with this, it will be a breeze to write all the required unit tests, based on the <code>genericScaleTest</code>


such as:

<code>
    it('scales numbers down such as centimetres to metres', function(done) {
        genericScaleTest("scale", 0, 100, 0, 1, false, 55, 0.55, done);
    });
</code>


Thoughts? Thanks!