The directory cache and the database's Load to RAM feature
each result in a much better user experience.
But, when both features are enabled at the same time, it
can take a very long time on older players - easily several
minutes for larger libraries - until all of the database's
dircache references have been updated.
Include a 'Quick' option that causes the database to ignore
dircache references which can *significantly* reduce disk
activity after booting.
Change-Id: I25ae779c97d03885b06d5a28d8be55c0d05692a5
3ce3b102dd