Terse function names are used to make usage not stutter. For example:
```go
err := error.Forbidden("you shall not pass")
```
At the moment they are all the same fundamental `MatrixError` type. This will
be bad if we ever want to `switch` based on the kind of error. I'm hoping we
won't ever need to introspect into errors like this: ideally these errors would
be created purely for immediately being returned in an HTTP response.
`MatrixError` implements the `error` interface.
* Move partition offsets sql to a separate file
* Move event types sql to a separate file
* Move event state key sql to a separate file
* Move room sql to a separate file
* Move events sql to a separate file
* Move event json sql to a separate file
* Move state snapshot sql to a separate file
* Move state block sql to a separate file
* A kafkaesque room event consumer for the roomserver.
Implement the main input loop for the roomserver.
It will receive events from a kafkaesque event source and track
where it is in the stream.
It currently does nothing with the events it consumes.
