posix/aio*: Added notification on request completion

The patch adds the generation of a notification after an Asynchronous I/O
request has been completed. The notification is generated using the aio_sigevent
filed in the aiocb struct, as defined by the posix specifiations.
A new control, ensuring the validity of the field, is added on each call to
aio_read(), aio_write() and aio_fsync().
The patch also adds tests to cover the new code, and fixes formatting errors of
various aio files.

cpukit/include/aio.h

@@ -36,7 +36,6 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-
 #ifndef _AIO_H
 #define _AIO_H
 
@@ -160,6 +159,7 @@ struct aiocb {
  *         - EINVAL the starting position of the file is past the maximum offset
  *           for this file.
  *         - EINVAL aiocbp is a NULL pointer
+ *         - EINVAL aiocbp->sigevent is not valid.
  */
 int aio_read(
   struct aiocb  *aiocbp
@@ -178,6 +178,7 @@ int aio_read(
  *         - EINVAL invalid aio_reqprio or aio_offset or aio_nbytes
  *         - EAGAIN not enough memory
  *         - EINVAL aiocbp is a NULL pointer
+ *         - EINVAL aiocbp->sigevent is not valid.
  */
 int aio_write(
   struct aiocb  *aiocbp
@@ -213,7 +214,6 @@ int aio_error(
   const struct aiocb  *aiocbp
 );
 
-
 /**
  * @brief Retrieve Return Status of Asynchronous I/O Operation
  * 
@@ -284,6 +284,7 @@ int aio_suspend(
  *            - EINVAL A value of op other than O_SYNC was specified.
  *              The current implemetation only supports O_SYNC.
  *            - EINVAL aiocbp is a NULL pointer.
+ *            - EINVAL aiocbp->sigevent is not valid.
  */
 int aio_fsync(
   int            op,