clean: Call setters.

* src/core/java/com/dataiku/dip/partitioning/TimeDimensionValue.java:
  Instead of a direct access to the attributes.
style: Delete a printStackTrace.

* src/dctc/java/com/dataiku/dctc/command/Alias.java: Replace it by an
  error message.
hack: How to compile.

* hacking/hacking.org: Here.