Homme: Some minor tweaks related to print to screen

[bartgol]

Namely:

• allow iulog to be settable if SCREAM is defined, rather than hard coded to 6 (stdout);
• replaced a couple of print to screen with write(iulog, *);
• allow to pass output stream to SimulationParams::print.

Plus, fixed compiler warning related to SimualtionParams members initialization order.

homme_integration and e3sm_developer passed on Chrysalis.

[BFB]

[bartgol]

homme_integration and e3sm_developer both pass on chrysalis.

[bartgol]

Retested on chrysalis after the last two commits, and the two testsuites still pass.

[ambrad]

Is this ready for merging?

[bartgol]

Yes, I'm no longer touching it.

[ambrad]

I'll merge this on Monday if next is open then.