In order to keep all test-related files within one folder,
this commit creates a new folder 'test/', moves the
test-related files into it and intrdocues a second makefile
within this folder dedicated to run the tests.
The original makefile still contains a 'test' target, but simply
delegates this task to the second makefile.
(fixesdavid-a-wheeler/flawfinder#11)
Signed-off-by: Julien Hachenberger <julien.hachenberger@sit.fraunhofer.de>