Implements kd.Key#press.  Fixes #4. v.0.1.3.

Squashed commit of the following:

commit 730d0d8ad1f1e7d08c729e8f08b3098b13b66390
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat May 18 16:53:13 2013 -0700

    Updates README.

commit fe6bcb20cd5823c4b722f1a7c7bbf7afdd57edf6
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat May 18 16:47:32 2013 -0700

    Generate dist/ files.

commit 252f10e8aa367420760c9db888a35f1267d4fe01
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat May 18 16:44:28 2013 -0700

    Refactors handlers.

commit 010eaddecb70f6cf45441713c211901991ce790e
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat May 18 16:27:14 2013 -0700

    Implements Key#unbindPress.

commit d390acafc99f9f3fe641d07307e7a35c1c677e7b
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sat May 18 16:21:15 2013 -0700

    Implements Key#press and some test code.