Allow user to configure what is written to standard output

[kvcalvin]

When you run hector coupled to GCAM, the model prints a bunch of statements to the standard output (ODE solver...). I'd like to choose what I see in standard output.

[bpbond]

This is basically a duplicate of Hector command-line options #69 . Closing.

[pralitp]

I just ran across this again. It turns out this issue is easier than parsing logging levels. The carbon cycle model is printing messages to both the logger and cout. That latter obviously doesn't care about logging levels. I'll open a pull request to remove the duplicative cout statements and turn on the "echo to cout" option on the logger instead.