Server
Change binding to 0.0.0.0
Added to .gitignore
Add try/except to ExternalRequestStage's bind
Add processor to ExternalRequestStage
Add try/except to InternalRequestStage's bind
Fixed removal of finished coordinators

Problem:
- list of coordinators was throwing an exception if a coordinator was
removed during iteration

Fix:
- coordinators to be removed are added to a separate list and removed
afterwards.
Fixed removal of failed membership checks

Finished checks are now handled and removed after iterating through the
list.