Random coverage

Random timeouts

======================================================================
ERROR: test_base (Orange.widgets.utils.tests.test_webview.WebviewWidgetTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/build/biolab/orange3/build/travis-test/Orange/widgets/utils/tests/test_webview.py", line 22, in test_base
    svg = self.process_events(lambda: w.svg())
  File "/home/travis/build/biolab/orange3/build/travis-test/Orange/widgets/tests/base.py", line 196, in process_events
    raise TimeoutError()
TimeoutError