CYKLO-927 Use DirectoryReader for all open / checking if open and other opening related tasks.
CYKLO-927 In order to CommitUserData one must obtain instance of DirectoryReader and invoke getIndexCommit method which returns IndexCommit object which has method to retrieve 'old CommitUserData' named getUserData.
CYKLO-927 Change methods to return NIOFSDirectory instead of LedgeFSDirectory.
CYKLO-927 Change to use utility to obtain Directory instance.
CYKLO-927 Delete LedgeFSDirectory which has been replaced by NIOFSDirectory 300 lines less in a code base is a good thing.