Checkpointer: checkpoints will now be written persistently and renamed, so as...

Checkpointer: checkpoints will now be written persistently and renamed, so as to ensure that no partially written checkpoints become visible to other facilities, such as replication

Snapshots: fixed bug in DefaultSnapshotConfig, added functionality to retrieve all snapshots of a database

git-svn-id: https://babudb.googlecode.com/svn/trunk@136 d4c7dd96-b7b2-11dd-893d-d98698f66bbf