https://issues.apache.org/jira/browse/ARTEMIS-163
On this pass I'm just converting the native layer to a simpler one.
It wasn't very easy to change the alignment at the current framework,
so I did some refactoring simplifying the native layer
The volume of the nubmer of changes here is because:
- The API is changed, we now don't close the libaio queue between files
- The native layer won't use malloc as much as it used to, saving some CPU and memory defragmentation
- I organized the code around nio and libaio
Clebert Suconic