Squashed commit of the following:

commit 82f32193d1a799e2ada238868e64a5debdc30359
Author: Stephen Diehl <stephen.m.diehl@gmail.com>
Date:   Sun Mar 23 18:13:59 2014 -0500

    mean / sum

commit 05214d2fe0760737b9ed50996234a78f4afeb516
Author: Stephen Diehl <stephen.m.diehl@gmail.com>
Date:   Sun Mar 23 15:56:00 2014 -0500

    added padding

commit f8a7807a92f76b9887aca2f8a975b686ed032e7d
Author: Stephen Diehl <stephen.m.diehl@gmail.com>
Date:   Sat Mar 22 19:42:41 2014 -0500

    better index alignment

commit a74c4038f4192756285161b2f609cc843215d157
Author: Stephen Diehl <stephen.m.diehl@gmail.com>
Date:   Sat Mar 22 18:47:41 2014 -0500

    add traverse

commit 844ab5c024bfb0e76f5b8832f359fcb114c0aa5e
Author: Stephen Diehl <stephen.m.diehl@gmail.com>
Date:   Sat Mar 22 18:05:19 2014 -0500

    new work