- use functionObject writeInterval not timeInterval.
No change in behaviour since the missing writeInterval is treated
as '1' anyhow when using 'timeStep' for the writeControl
- consistent use of 'adjustable' vs 'adjustableRunTime'
- prefer '#eval{ vector(...) }' to calling '#eval' multiple times
- update TimeState access methods
- use writeTime() instead of old method name outputTime()
- use deltaTValue() instead of deltaT().value()
to avoids pointless construct of intermediate
