Incrementer fields can now be controlled with the mousewheel.

Squashed commit of the following:

commit 4edfe6767192b972e68e6aaaf74765333d83be8b
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat Oct 19 15:32:39 2013 -0500

    Reverses incrementer scrolling.

commit 9f508dfdc134b0f573c9311ff223bb06490b6e71
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat Oct 19 15:30:06 2013 -0500

    Builds 0.3.6.

commit 45f7b2f4710700a286c35250b32608c2e5efee48
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat Oct 19 15:27:35 2013 -0500

    Listens to window scrolling when incrementer is focused.

commit ad09e8bfc4f684ca92a4d00d72b6c377c6eb2f0f
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat Oct 19 15:13:53 2013 -0500

    Starts on mousewheel support.
Merge branch 'master' into gh-pages