[svn-r20269] Interim checkin of AIO/VFD code.
Updated AIO/VFD branch from trunk and dealt with bugs and incompatibilities
as necessary. Amongst other things, this required deleting a number of files
unrelated to the AIO/VFD work as detailed below.
Modified test/vfd to be express test aware, and to issue notices when skipping
tests.
Added support for the H5_HAVE_AIO #define. When H5_HAVE_AIO is not defined,
all but the top level AIO code is Eifdef'ed out.
With the help of Mike M, updated the configure code to define H5_HAVE_AIO
for Linux and freebsd. H5_HAVE_AIO is undefined in all other cases.
Tested serial and parallel on Phoenix. Tested serial on jam, heiwa, linew, and
freedom.
