Support for incremental backup and supporting log-only backup cursors.
Also log archiving via truncate with the backup cursor.  #1183
Incremental backup test. #1183
Change print to self.pr. #1183
Merge branch 'develop' into incremental-backup
Merge branch 'develop' into incremental-backup
Changes to allow recovery to be run between incremental backups. #1183
Lint.
Remove debugging remnant.
Fix code movement bug in opening backup file.
Add restriction and error checking for having run recovery.  Update
examples and test. #1183
Lint.
Update backup documentation. #1183
Merge branch 'develop' into incremental-backup
Review comments. #1183
Merge branch 'develop' into incremental-backup
Merge pull request #1370 from wiredtiger/incremental-backup

Incremental backup