More partitioners

This introduces more partitioning options: daily, hourly and whatevery.
Also upgrades Joda-time 1.6 to 1.6.2.
To be considered: remove DefaultPartitioner.
Because 'daily' is the default target for camus-sweeper. But now I think of it, you have to change the default source for camus-sweeper anyway. I am fine with changing it.