CMakeLists.txt:
  Add plugin/semisync subdirectory
mysql-test/mysql-test-run.pl:
  Check for semisync dll for Windows
mysql-test/suite/rpl/r/rpl_semi_sync.result:
  Update result file
mysql-test/suite/rpl/t/rpl_semi_sync.test:
  Test semi-sync on Windows
plugin/semisync/semisync_master.cc:
  Define gettimeofday for Windows