Adds a widget for defining custom easing curves.

Squashed commit of the following:

commit 20edf1ed821c13fbe83d108326cae855f33a10d2
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Wed Sep 18 11:05:50 2013 -0500

    Builds and tags 0.3.0.

commit b0aca035a7fb5774e499f33bf04ce3fb3124e0cb
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Wed Sep 18 11:01:20 2013 -0500

    Adds instructions for Bezier curve editing.

commit 94a02f395404327069077fef9fa0c1cb23ef921c
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Wed Sep 18 10:51:15 2013 -0500

    Updates Bezier control point fields when Bezierizer element is changed.

commit c8710f51b8c53a2d0f04961ff29bf20a925156e7
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Wed Sep 18 10:35:38 2013 -0500

    Fixes Bezier sync issue for paused animations.

commit 6f115cf31f13ad989239dd6c9b3b7e450695ee2a
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Wed Sep 18 10:29:44 2013 -0500

    Removes old custom easing code.

commit 7c8fbacedfc3c8983c8aab49b04647c780ad046e
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Wed Sep 18 10:21:25 2013 -0500

    Fixes bezier curve and rotation sync bug.

commit 158b8ce399daa4b833d6b8d26224ae865e5f41e6
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Wed Sep 18 10:07:31 2013 -0500

    Stores and recalls custom Bezier curves.

commit 9cb415fc566526a7ede2095c4a2fadd07ebe2730
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Wed Sep 18 09:04:24 2013 -0500

    Hooks up Bezier incrementers to UI update.

commit 595c9a5edc704a2862d6d113f8fb037eafda3207
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Wed Sep 18 08:37:08 2013 -0500

    Changing Bezierizer widget updates custom easing formula.

commit 416ab64481c07cbbdaac4662918059e7ec67aee0
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Sep 17 23:52:44 2013 -0500

    Adds addEasing method.

commit 7d2c07ebd9deaf8ec17823a8da778f6e4e003516
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Sep 17 14:50:54 2013 -0500

    Hooks up Bezier inputs to handles.

commit 5c044d0cd853b2e81fb2259b312926509206ce1f
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Sep 17 14:41:35 2013 -0500

    Hooks up onControlPointValReenter.

commit d868cbf0cd0a485028bb294a3dc4f46a72e9a448
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Sep 17 14:13:54 2013 -0500

    Sets up Bezier control point inputs as AutoIncrementerViews.

commit de0b1378c6ca0ea777c8028443b071a8012210d9
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Sep 17 11:23:57 2013 -0500

    Adds custom easing position fields.

commit 8423c75e615868a38bdfc182ef757a45924d5843
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Sep 17 10:59:42 2013 -0500

    Adds some DOM and styles for custom easing widget.

commit 546291bc04c5fa9c8875e354c10a1121f5fad899
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Tue Sep 17 10:30:28 2013 -0500

    Drops Bezierizer into the page.