Adds mousewheel scaling feature.

Squashed commit of the following:

commit 2ee13df4a9d2e6fd994b5716407568b38814f53a
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Aug 5 08:35:27 2014 -0500

    Updates README.md.

commit 85fefbfc8098a87d6df036cbf700118bab775fe7
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Aug 5 08:31:52 2014 -0500

    Cleans up math a bit, revs to 0.1.0.

commit 59ec418f23c9b4641cf3b84a3b60846da7373f6c
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sun Aug 3 12:22:27 2014 -0500

    Prevent NaN deltas if there was no mouse movement.

commit 4217f22dcbab2890f2ed5c39e5cc9e4055d32451
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat Aug 2 15:12:22 2014 -0500

    Adds support for programmatically setting scale.

commit 5f7ae694bcfa80b688d2c5e8b83249dd0e5440b7
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat Aug 2 14:26:00 2014 -0500

    Limits scaling precision.

commit 3d98d2fa90648e75a57d4ab62efb82c2355f0ba0
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Thu Jul 31 08:36:42 2014 -0500

    Improve handling of mousewheel interactions when the Cubelet is shown.

commit d35d1753887f10d4e3279cfbd187e70b8df403a2
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Thu Jul 31 08:11:17 2014 -0500

    Adds support for negative scaling.

commit f37d5a0add99a839ca8bdc5e8f24f12d3939e6a9
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Jul 29 21:55:17 2014 -0500

    Cleans up docs, adds scale output to sandbox.html, rebuilds binaries.

commit aea1c3424dc9490193b1601422ef4f4fd79c3fe9
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Jul 29 21:48:47 2014 -0500

    Fixes rotation responsiveness.

commit 87229c9889b6963bf9633f594586cbc83e26cacc
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Jul 29 21:38:07 2014 -0500

    Make mousewheel scaling work better in Firefox.

commit 611fc22a0726b2d13f78dea5942b16e09e27953d
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Jul 29 08:55:54 2014 -0500

    Makes mousewheel a little more responsive in Chrome.

commit 7062518ab4832c13a4aff2467e06fada8493c151
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Jul 29 08:26:20 2014 -0500

    Switches from translateZ to scale.

commit a62afe9e055c3a8a7c2668f5c55c0dc83daf4953
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Mon Jul 28 21:40:12 2014 -0500

    Syncs zoom to circle.

commit c794614b027b155ca6dbf42555a62e622413a44b
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Mon Jul 28 21:14:48 2014 -0500

    Implements basic cube zooming.