corda metrics should be obtainable for the reversible model as well

[cdiener]

Currently print called for a CORDA optimizer instance will give infos in the following form:

build status: reconstruction complete
Inc. reactions: 2238/5351
 - unclear: 657/2485
 - exclude: 95/863
 - low and medium: 922/1345
 - high: 564/658

However, this is based on the irreversible models and does not consider that the reversible reaction is added along with all included reactions. So it would be better to change those metrics to the reversible case or allow for an option to specify the behavior.

[cdiener]

done in 392fcce.