This patches fixes the known issues with Async NDB API support,
and enables it by default.
Fix output from lintTest so that test -q is really quiet.
Some refactoring of NdbTransactionHandler.
Fix NdbSession for previous commit (no more DBTransactionHandler.state)
NdbConnectionPool.close():
If close results in close of underlying Ndb_cluster_connection, 
then callback will not be invoked until the connection is really closed.
Some try/catch wrapping for more readable tests.
Move blocking getIndex() calls back into the worker thread.
 Improve error handling in NDB adapter
 Rewrite tests in InsertDuplicateTest.js to use try/catch --
  this gives slightly more cryptic results but much more readable test code.
Rename "mysql_code" property of NdbError object to "handler_error_code".
MySQLConnection
  add parameter to constructor of DBSession
  the index parameter keeps track of the index into connection pool open connections
  call felix connection end when DBSession is closed

MySQLConnectionPool
  provide open connection index when calling DBSession constructor
Close the session if tests are run with fail_verify_integraltypes.
Close file-scoped session at the end of each test.
Close session when using fail_verify_t_basic
Remove Test.setup and Test.teardown
SessionFactory
  implement getOpenSessions:
    return the sessions that are not yet closed

driver
  clean up after all tests:
    get open sessions and close them all
SessionFactory
  close all open Sessions when closing SessionFactory

driver
  close session factory at end of test
Reimplement Transaction
  allow state change to be reported in callback for commit and rollback
  state machine explicitly sets transaction state
  allow user callback for begin and setRollbackOnly instead of throwing

UserContext:
  change the transaction state after commit or rollback but before user callback
  set transaction rollback only for failed operations
    except for find of non-existent row (it is not really an error)

RollbackOnlyTest:
  test find non-existent row not setting rollback only
  test persist duplicate key setting rollback only
  test delete duplicate key setting rollback only
  test update nonexistent row setting rollback only

TransactionTest:
  check error reported in callback for idle commit, idle rollback, idle setRollbackOnly
  check error reported in callback for active begin
  check error reported in callback for rollbackonly begin
  updated failure reports to include test number
Add default implementation test
merge