Fix for the data/unwrap

[zoka]

Hi Zach,

Could you please review Penumbra patch at https://gist.github.com/1102320

Changes:

- there were couple of typos in Penumbra test code (app/periodic-
update! and app/start)

- partition-all and flatten need not be specified since they have been
moved to core

- texture/unwrap was returning a typed byte buffer instead of array,
so helper function buffer-to-array was added. This bug caused
number of tests in gpgpu.clj to fail.

Regards
Zoka