maxscale-system-test changed in order to control test environment by itself.
Every test checks which machines are running, compare with list of needed machines
and start new VMs is they are missing in the running machines list.
Tests are executiong MDBCI commands, MDBCI executable should be in the PATH
* add possibility to run named test
* remove sysbench_dir
* remove unsupported in 1.0 sysbench options
* exculed ReadConnRouter sysbench test
* fix sysbench table name
maxscale-system-test/set_env.sh script is slow because it checks if MariaDB start command is mysql or mysqld
Now all versions can be started with 'mysql' except MySQL 5.5 which is not supported
