Use TimeoutTimer instead of setTimeout for grace period

This will make it a bit more convenient to unit test.
Move the soft kill function to its own module

I want to unit test it
Configure timeout in suite runner rather than softKill

It will eventually be configured by config parameter
Unit test soft_kill.js
Make it possible to inject softKill into the suite runner

For testing purposes
Make graceTime configurable
Rename disallow_only to disallowOnly

For consistency. No other parameters to the suite runner are in underscore_case.
Move tests around a bit

SIGINT and SIGKILL tests are really timeout things
Test the graceTime parameter to the suite runner
Immediately send SIGKILL when softkilling with timeout 0
Fix linter errors
Fix broken test

Before this fix, test coverage was reporter in the middle of running tests
Merge pull request #37 from pereckerdal/grace-time

Make it possible to configure the grace period before kill