the link() and unlink() methods from Value are only called from the backend, so pass in the Database instance.
That lets me remove the removeLob() method from LobStorageInterface.

rename PageStore#systemSession to PageStore#pageStoreSession, to distinguish it from Database#systemSession

LobStorageBackend is only ever constructed from Database, so let's use it directly

This is a cleanup targetted at allowing us to fix a deadlock issue.

   //## Java 1.6 ##
comments. We no longer need them, since we depend on Java6 or better now.

fix connection leaks in the testing code. Prevents my machine from running out of sockets during soak tests

fix some connection leaks, and an assignment error in testRecoverLobInDatabase() where it was creating the statement from the wrong connection