[Lang] BigDecimalStatistics proposition

[Aleksander Ściborek]

Hi, I've come up with the idea of making easier using Stream with
BigDecimal class.
The idea is to create BigDecimalStatistics class which provide a convenient
way for calculating max, min, average and sum from BigDecimals from Stream.
I think that it's very suitable for commons library.
Should it be implemented in commons lang or commons math? I believe that
it's more suitable for commons lang
This is a link to Jira Ticket : LANG-1459
<https://issues.apache.org/jira/browse/LANG-1459>
Aleksander