`bp.store` - consider refactor with event callbacks

[michbarsinai]

const eB1 = Event("b1");

bp.setCallback(EventSet("p1"), function(event, storage){
    storage.put("a", event.data.aCount);
});

bthread("b1", function (){
    waitFor( Event("A") );
    bp.store.put("v", "b1");
    bp.log.info(bp.store.get("v"));
    request(eB1);
});

bthread("b3",function(){
    request( Event("A") );
    bp.log.info(bp.store.get("v"));
})

Then cancel/deprecate bp.store.put