Add auxiliary functions to stochasticBandits.wppl
Add auxiliary functions to stochasticBandits.wppl

One function builds a start state, one function takes a table of
utilities of prizes and returns a utility function.

agentmodels/webppl-gridworld,agentmodels/webppl-gridworld,agentmodels/webppl-agents,jsalvatier/webppl-agents,jsalvatier/webppl-agents,jsalvatier/webppl-agents,agentmodels/webppl-gridworld