WT-2330: in-memory configurations should not create on-disk collection files

Create a pluggable OS layer, add in-memory version so in-memory
configurations don't create on-disk files.

Notes:

The WiredTiger library no longer uses FILE * objects, the file descriptor
and stream functions now use the same open and close functions, and both
have a WT_FH handle.

The sync/async versions of __wt_fsync have been merged, there's now a
boolean flag that indicates wait/no-wait on the flush.

The transaction log's print-log function no longer supports unspecified
handles, output is always to stdout (which the wt utility redirects into
another file as needed).

0 files changed, 0 insertions, 0 deletions