Fix for issue#30 - Improve initialization of randomizer

Because it is independent of the id, the randomizer can be initialized
outside of "onCreate" method. This is less error-prone.
Merge pull request #32 from matthieumorel/issue30

Fix for issue#30 - Improve initialization of randomizer
Merge pull request #35 from abifet/master

Fix for issue#33: Solved paralelization problem in DistributedClustering
Merge pull request #7 from yahoo/master

Fix for issue#30 - Improve initialization of randomizer