New log level "notice" set to python log level 25 maps to syslog priority
LOG_NOTICE. Used for some messages in the proxy server, but will be available
to all apps using the LogAdapter returned from get_logger. Cleaned up some
code in get_logger so that console logging works with log_routes and removed
some unneeded bits. NamedFormatter functionality was split between LogAdapter
(which now inherits from logging.LoggerAdapter) and TxnFormatter (which now is
only responsible for adding the log records txn_id).
The proxy server app now configures a separate logger for access line logging.
By default it will use the same settings as the regular proxy logger.
LogAdapter.tnx_id so that it works with multiple calls to get_logger, fixed
common.middleware.catch_errors to only call get_logger if it needs too, renamed
x-cf-trans-id to x-swift-tnx-id