Test system for MaxScale.
Every test/makefile have the following targets:
 cleantests 	- clean local and subdirectories' tests
 buildtests	- build all local and subdirectories' tests
 runtests	- run all local tests
 testall	- clean, build and run local and subdirectories' tests

Tests for directory random_dir are always in its subdirectory, in this case in random_dir/test . If random_dir has subdirectories with tests, random_dir/child_dir, for example, tests of child_dir can be started from random_dir/test/makefile where make -C child_dir/test <test target> is called.

See MAXSCALE_HOME/test/README for further information.
Merge https://github.com/skysql/MaxScale