Fix table updates with custom extractor.  We were stashing a copy of the new value in the table cursor value, but that copy was being overwritten when invoking the custom extractor.

refs #1199
Avoid the "bool" flavor of compare-and-swap primitives: clang 3.5.0 produces bad code.
Flush checkpoint handles prior to taking schema lock.

This should save time when flushing again while holding the schema lock.
Merge pull request #1351 from wiredtiger/checkpoint-sync-early

Flush checkpoint handles prior to taking schema lock.
Merge branch 'develop' into directory-sync-log-files