Compile error: Not closing event store

...cause it has no `Close()` function anymore.
661a605dd7cec9500af45984c8f255c56a3de066 introduced this compile error.
Moving files to `eventstore` package

...to separate features into packages for easier maintenance.

Things currently don't compile.
Updating package paths to use `eventstore`
Updating go files with new package name: eventstore
eventstore.NewEventStore(...) => eventstore.New()
Reusing `Event` in `StoredEvent`

This opens up for more reusable code.
Documentation improvements
Support in-memory store on startup

This makes it possible to invoke `gorewind` for 3rd party applications.
Minor: Use full import name if possible

Seems like the way to Go.
Minor: Reusing error check

...to make less code.
Rename: Server.Run() -> Server.Start()

'Start' is the opposite of 'Stop'.
Server tests for starting and stopping

The tests currently fail.
Bugfix when stopping server

It failed everytime. Tests still fail.
Patching to support latest GoZMQ

...should possibly make a fork of the project in the future...
Minor: Logging improvement
Minor bugfix: Returning the correct error
Shutting down `publishAllSavedEvents` correctly
Making `Server.Start()` asynchronous

Call `Server.Wait()` to make it async.
Fixing a race condition

...that made it possible to start multiple instances of the same server.
Running `server` tests in parallel