merging with climate yield shock changes

data/halfdeg/yieldshockmap.txt

data/sims/ssp_params.csv

data/sims/ssp_sims11.csv

src/ac/ed/lurg/ModelConfig.java

src/ac/ed/lurg/ModelMain.java

src/ac/ed/lurg/country/CountryAgent.java

src/ac/ed/lurg/shock/YieldShockItem.java

src/ac/ed/lurg/shock/YieldShockReader.java

src/ac/ed/lurg/shock/YieldShocks.java

src/ac/ed/lurg/yield/YieldResponse.java

src/ac/ed/lurg/yield/YieldResponsesItem.java