move Store to dbp-api, update dependencies
Fix an obvious bug of casting to wrong type
Move some API classes and interfaces to sos-env;
limit direct usage of ContextLink
compiles-untested:
move debug flag from ServiceExertion to SorcerEnv;
move more classes to sos-env (API);
move Accessor initialization entirely to static method in Accessor;
extract ComplexExertion from Job and use it instead;
move StopWatch to sos-util