Use chill.ClosureCleaner on all functions

[johnynek]

Scala captures a reference to the enclosing object always, even if the function doesn't reference that object.

When the job is serialized, this can dramatically increase the size, and cause some things to need to be serializable that don't really need to be.

A fix for this is to go into the few Cascading Operations we have, and call ClosureCleaner(fn) on all the functions passed into constructors.

This could potentially dramatically reduce this size of jobConfs and speed up submission times. Also, it could make it easier for users by reducing the number of cases where they need to hack around weird serialization errors.

[johnynek]

addressed in: #273