Rename OutputStreamAthenaPool.OutputStreamAthenaPool module to OutputStreamAthenaPool.CreateOutputStreams

Having a module with the same name as the package name causes problems with syntax like:

```from OutputStreamAthenaPool.OutputStreamAthenaPoolConf import ...```

in python 2.7, so the module has been renamed to `CreateOutputStreams` and all references in the code
have been adapted.