Merge pull request #333 in HDFFV/hdf5 from merge_page_buffering_07 to develop
* commit '4fad103187db9095afc8eab90b5f5544feb1d19b':
Bring changes to I/O parameters from page_buffering branch.
Merge in reentrency changes to "make space in cache" from page_buffering branch.
Minor cleanups and bring over "prefetched dirty" fixes for entries loaded from a cache image.
Remove some usage of "prefetched_dirty" flag (which hasn't been merged from the page_buffering branch yet. Also, bring over improvements to flush candidate entries for parallel code.
Align with incoming page buffering changes: minor cleanups, centralize removing entries from collective metadata read list
