Added shutdown method.
Merge branch 'master' of github.com:cojen/Tupl

Conflicts:
	src/main/java/org/cojen/tupl/Database.java
Added support for memory mapped I/O.
Added preview view support.
Merge remote-tracking branch 'remotes/origin/master' into map
Added prefix view support.
Merge branch 'master' of github.com:cojen/Tupl
Comment HTML cleanup.
Added replication events.
Add file mapping tests.
Merge remote-tracking branch 'remotes/origin/map'
Comment clarification.
Release promoted locks when fully rolling back a transaction.
Fully commit transactions which were logged as such, preventing rollback if undo log scope commit is lost.
Shutdown ensures complete checkpoint before closing the database.
Remove unused parameter.
Fix handling of large keys when internal nodes split.
Prevent NPE when closing after open failure.
Merge remote-tracking branch 'remotes/origin/master' into compact