Removed some clutter.
Minor refactoring and some improvements.
A test for EclatMiner is added.
Min and max sizes are now supported in EclatMiner.
Dist-Eclat now uses only one EclatMiner for both phases.

- EclatMiner now always needs a prefix.
- PrefixItemTIDsReported calculates TIDs by itself.
Removed some unused code.