* Do tests with pytest to run them in parallel

* attempt to handle merge commits better for PR test path

Similar to how we solved this for travis

* Clean up imports

* don't run valgrind if not specified slow_test

* Fix functest after initializer rename

* upload tests results as junit

* Upload test-common files since #200 got merged

* Catch test results upload failure

This way we can properly raise skiptest

use randombytes in functest

Got dropped by the rebase

Work around missing clang-tidy on Travis

Also check if valgrind is available

Modify the tests to no longer construct the classes multiple times and
to have them make use of the new helpers.make() function.