Adding new and cleaning up old null handling.

Signed-off-by: Timo Kinnunen <timo.kinnunen@gmail.com>
Added simple no-argument toList methods to primitive streams.

Signed-off-by: Timo Kinnunen <timo.kinnunen@gmail.com>
Renamed primitive stream-building methods to make them more
discoverable.

Signed-off-by: Timo Kinnunen <timo.kinnunen@gmail.com>