psblas3:

Version number string &  docs.

docs/src/intro.tex

@@ -283,6 +283,10 @@ are classified as:
   is guaranteed to be the same.
 \item[local] Each process has its own value(s) independently.
 \end{description}
+To finish our general description, we define a version string with the
+constant 
+\[ \verb|psb_version_string_|\]
+whose current value is \verb|3.0.0|
 
 \subsection{Application structure}