Two changes of testsuite (killing redis and new option)

remove mentions of VM in comments

allocate alternate signal stack, change of sigaction flags for sigterm

Structure field controlling the INFO field master_link_down_since_seconds initialized correctly to avoid strange INFO output at startup when a slave has yet to connect to its master.

Print milliseconds of the current second in log lines timestamps. Sometimes precise timing is very important for debugging.

When the user-provided 'maxclients' value is too big for the max number of files we can open, at least try to search the max the OS is allowing (in steps of 256 filedes).

chkconfig in install_server.sh doesn't work because of a typo

occurs when two or more dbs are replicated and at least one of them is >db10