Updating Future API

add #do_then for chaining
add #fail for failure indication
Add TriggerResult wrapper for World#trigger method

rename planed to planned
catch also Exceptions in Action#with_error_handling

re-raise the lower ones
Use common class for TriggerResult instead of Algebrick

fix termination tests
minor core readability improvements
Graceful termination of RemoteViaSocket executor

changing terminate! to blocking
better micro actor termination
update requirements to Algebrick 0.3.2
fix - allow only one update_progress run on a given action
Do not return from World#initialize until executor isn’t fully initialized

fix: „log writing failed. KeyError“
better error when something is not found in DB
Merge pull request #53 from pitr-ch/master

Updating Future API
Log state transitions