Merge branch 'hotfix/1.3.1'
socket controller optimisation for large deployment

a) increase the number of socket controller contexts to 1024
   this concerns all the process excepted rozofsmount and exportd

b) increase the number of af_unix/af_inet contexts to 1024

c) exclude the TCP connection for the xmit/receive prepare

   for the TCP (AF_UNIX) connection the xmit fsm has been change in
   order to handle differently the case of the congestion: it directly
   assert the FD_SET since the prepare (xmit/recv) is not used anymore
   for those connection types.

d) change the process for finding out the sockets conerned by the select(return)
e) Debug facilities
    increase the max buffer size to 384K

    add the topic "select_stats":
    -----------------------------
    [127.0.0.1:50003] rozofsmount 0> select_stats

    Per select call statistics:
    [0001] = 3136
    [0002] = 1
    [0006] = 1

    "cpu"
    -----
     add the prepare and socket searching upon select return cost in cycles:
     [127.0.0.1:50003] rozofsmount 0> cpu
     conditional sockets      : 5
     max socket events        : 6
     xmit/recv prepare cycles : 3875 cycles [2519339/650)
     xmit/recv receive cycles : 2161 cycles [1404691/650)
     gettimeofday cycles      : 1100 cycles [715333/650)
     rucRdFdSet 0x70dd80 (128) __FD_SETSIZE :1024 __NFDBITS :64

     "sockctrl"
     ----------
       provides the socket controller configuration for the current configuration.

       [127.0.0.1:50003] rozofsmount 0> sockctrl
       max number of socket controller contexts : 128
       scheduler polling period                 : 40000 us
       scheduler polling count                  : 16

       usage:
      sockctrl pollcount <value> : set number of polled contexts per activation
      sockctrl pollfreq <value>  : set activation period (unit is microseconds)
      sockctrl                   : display current configuration
Merge branch 'develop' of https://github.com/rozofs/rozofs into develop