Merge pull request #46 from iNecas/refactor

Major refactoring
Merge pull request #47 from pitr-ch/refactor

see commits pls
Merge pull request #49 from pitr-ch/refactor

make MicroActor safer
Save step ids under :step_ids instead of :steps when serializing execution plan
Action::Presenter and ExecutionPlan#actions

Usable for getting and aggregating data out of the execution plan
Merge pull request #50 from pitr-ch/refactor

Refactoring: pls see commit messages
Log ExecutionPlan state changes

and minor changes/fixes