* Rename Subfiling IOC "thread_pool_count" field to "thread_pool_size"
* Add simple HDF5 example for Subfiling VFD
* Subfiling VFD - never cache app topology as it may change
* Subfiling VFD - cleanup unused funtionality and tidy up some TODOs
* Subfiling VFD - tidy up subfiling error handling in H5subfiling_common.c
* Subfiling VFD - show number of failed I/O requests on close
* Subfiling VFD - Update file cmp callback after switching to MPI I/O VFD
* Amend RELEASE.txt with info about h5fuse.sh and Subfiling limitations
* Subfiling VFD - switch to using H5_basename and H5_dirname