Targetting 4.1

Proposal

Take the existing:

hazelcast/hazelcast/src/main/java/com/hazelcast/map/impl/proxy/MapProxyImpl.java

Line 916 in 4fed159

 public <R> Iterator<R> iterator(int fetchSize, int partitionId, Projection<Map.Entry<K, V>, R> projection, 

And create a public API in IMap which differs from the above in that it:

1. does not require partitionId but work

String representations of dataset objects are used for previewing their contents from the terminal. When converting a Dataset object to a string, we build a table using ascii characters. The current table has fixed width columns that do not take full advantage of the terminal real estate if the dataset only contains a few columns.

echo $dataset;

<img width="574" alt="Annotation

Introduction
There is a discussion regarding to purity estimation - see #620 . In order to cover this proposal, V-Measure should be implemented.

References
Article: V-Measure: A conditional entropy-based external cluster evaluation measure. Andrew Rosenberg and Julia Hirschberg.

Description
The functionality should be implemented for Python and C++ version. The following names