v4: Remame --timeout option (and associated EnginePackageSettings)

[ChrisMaddock]

To permit #437. --timeout is ambiguous as to whether it refers to the timeout of the full test run, or an individual test. I suggest renaming the option in v4: potentially --defaultTestTimeout?

[CharliePoole]

Yes. i'd look at the internal names too, including those used as TestPackage settings.

[CharliePoole]

@jnm2 @mikkelbu @rprouse

I lean toward "TestCase" rather than "Test" but --defaultTestCaseTimeout is rather long. What about just --testCaseTimeout?

[jnm2]

Sounds good!