Started playing around with type extensions and typebound

procedures.
Merged performance fixes from trunk.

docs/html/node8.html

@@ -85,6 +85,9 @@ in the library as follows:
   normally 8 bytes. 
 </DD>
 </DL>
+Moreover, the library defines a long integer kind
+<code>psb_long_int_k_</code> which normally corresponds to 64-bit integers;
+it is only used for the <code>psb_sizeof</code> utility. 
 
 <P>
 <BR><HR>