Changes decisionModel string in config options to decisionModels list of models

[colinhanrahan]

Progress made on #21

Updates:

• README: updates information for agentDecisionModel
• config.json: changes agentDecisionModel from string to list
• sugarscape.py: changes decisionModel string to decisionModels list, randomizeAgentEndowments() randomly picks from decisionModels for each agent but in separate cycles to maintain correct relative frequencies
• data/run.py: createConfigurations() should correctly create configurations from dataOpts["decisionModels"]. Objects in decisionModels can be model strings or lists of model strings.

TODO:

• [ ] check to see impact on data collection
• [ ] thoroughly test for bugs

[colinhanrahan]

Closing to work on locally.

[nkremerh]

Saw this was still closed. Feature has been added in b247906. Please check to ensure all requirements have been met.

[colinhanrahan]

Looks good for single simulation runs — I'll check more thoroughly soon. In the future, we will need to modify run.py for data collection on multi-model simulations. I had a fix for it on my branch, but it looks like we'll be overhauling data collection simulation setup soon anyway (see my comment on #46).