QA-273: Feature/python test runner

[dothebart]

replace fish and ps test launching facilities plus report generators for one python implementation

• the environment variable TESTSUITE_TIMEOUT defines a deadline to the tests, how much seconds should be allowed.
• tests are running in worker threads.
• main thread keeps control, launches more worker threads, once machine bandwith permits, but only every 5s as closest.
• tests themselves have their timeouts; testing.js will abort if they are reached.
• workers have a progressive timeout, if it doesn't hear back from testing.js for 999999999s it will hard kill and abort.
• if workers have no output from testing.js they check whether the deadline is reached.
• if the deadline is reached, SIG_INT[*nix] / SIG_BREAK[windows] is sent to testing.js to trigger its deadline feature.
• the reached deadline will be indicated to testfailures.txt and the logfile of this test.
• with deadline engageged, testing.js can send no more subsequent requests, nor spawn processes => eventually testing will abort.
• force shutdown of instances will reset the deadline, SIG_ABRT arangods, and try to do core dump analysis.
• workers continue reading pipes from testing.js, but once no chars are comming, waitpid() checks with a 1s timout whether testing.js is done.
• if the worker reaches 180 counters of waitpid() it will give up. It will hard kill testing.js and all other child processes.
• this should unblock the workers STDOUT/STDERR threads, and they should exit.
• the waitpid() on testing.js should exit, I/O threads should be joined, results should be passed up to the main thread.
• so the workers still have a slugish interpretation of the deadline, giving them the chance to collect as much knowledge as posible.
• meanwhile the main thread has a fixed deadline: 5 minutes after the TESTSUITE_TIMEOUT is reached.
• if not all workers have indicated their exit before this final deadline:
• the main thread will start killing any subprocesses of itself which it finds.
• after this wait another 20s, to see whether the workers may have been unblocked by the killing
• if not, it shouts "Geronimoooo" and takes the big shotgun, and force-terminates the python process which is running it. This will kill all threads as well and terminate the process.
• if all workers have indicated their exited in time, their threads will be joined.
• reports will be generated.

[dothebart]

for the moment this is required so we may spawn threads for containers in later ubuntus.

[jsteemann]

Non-Python files LGTM.
I am not in a good position to review the Python code in this PR though.