hacked default values for crops as fix of Carl's previous hack to produce valid plots. (I wish I were kidding) Will be resolved by gh-3, ebimodeling/ghgvc#53, ebimodeling/ghgvc#27, ebimodeling/ghgvc#4, ebimodeling/ghgvc#5
Merge branch 'master' of github.com:ebimodeling/ghgvcR
added crop defaults