the mapi clients now use the monet (4) queue: - each listen(stream,stream) builtin is registered in the req->accept function - the req is put in the normal work thread queue
the mapi clients now use the monet (4) queue:
- each listen(stream,stream) builtin is registered in the req->accept function
- the req is put in the normal work thread queue

for xquery, this means that after this fix parallel execution becomes possible
  (now execution is done inside the listen)

for sql, this means that it no longer needs to fork itself
  (a new mapi_nclients config variable should be used to control the max # of working threads)

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb