Upgrade ck to 0.4.1

I have a libphenom application that uses concurrency-kit extensively. It needs some things from ck that are not available in 0.3.0. This upgrades to ck-0.4.1 to make those things available.

There were some changes to libphenom that were necessary due to breaking api changes in ck (https://github.com/sbahra/ck/commit/3edb523da5f6c9dcea41879ceb6643dcc7bde305). I've updated job.c and job.h to use the new api.

The libphenom tests pass, and I haven't seen any issues in my application level testing.

Some questions:

1. Does libphenom have a better way to update ck than copying in the code for the new tag?
2. Is there a preferred way to benchmark these changes to make sure they're not regressions?