Add the first two tests for {{{DB_ENV->log_archive}}}.  Fix up some memory leaks.  Add {{{LSN*}}} to all the {{{toku_log_*}}} functions so that {{{toku_logger_txn_begin}}} can use the LSN as a txnid.  Addresses #75, #83, #392.

git-svn-id: file:///svn/tokudb@3004 c7de825b-a66e-492c-adef-691d508d4ae1