Make configuration global

SuiteRunner listens for SuiteConfiguration and propagates this event to
each spec monitor.
This way default values can be defined once for each Suite run, not for
each spec.
Generate random seed only once

When not set, generate the seed for randomizing specs order only once
for suite run, this way the same order can be repeated.

The seed used is printed when the suite starts (either set or
generated).
Add timeout to configuration