#3 Update String concatenation rule

[nb_]

We need to look into the rules which deal with string
concatenation. An interesting article and analysis
about when to use it and when not can be found at:

http://wiki.java.net/bin/view/Javapedia/AlwaysUseStringBufferMisconception

We need to investigate whether the statements made in
the article apply to the rules implemented in QJ-Pro.