Bookkeeper API changes for initial Bookkeeper release

Changes are as follows.

BookKeeper#createLedger, parameter is named passwd, "Key" used in LedgerHandle api
BookKeeper#getBookieClient shouldn't be public
BookKeeper#createComplete shouldn't be public
BookKeeper#openComplete shouldn't be public
BookKeeper#deleteComplete shouldn't be public
BookKeeper#halt could be changed to close(), should throw a BKException

LedgerHandle#getLedgerKey passwd is used in BookKeeper, should possibly be private
LedgerHandle#getLedgerMetadata shouldn't be public
LedgerHandle#getDigestManager shouldn't be public
LedgerHandle#getDistributionSchedule shouldn't be public
LedgerHandle#writeLedgerConfig shouldn't be public
LedgerHandle#addEntry should return void, errors should go in an Exception
LedgerHandle#readComplete should not be public
LedgerHandle#addComplete should not be public
LedgerHandle#readLastConfirmedCompelte should not be public
LedgerHandle#closeComplete should not be public

ASyncCallback#RecoverCallback shouldn't be public