don't log an error level message if the json database does't exist (yet), just a debug.  closes #509

when starting up processes for local development or under the test harness, start them serially waiting for each process to bind before starting tests.  issue #556

add the dbwriter process.   it's not yet hooked up, but starts up and runs, and included in health check.

reorganize browserid process - break out view serving and wsapi handling.  preparation for dbwriter split.  issue #460

close #408

issue #553

close #552

close #544

fix test harness hangs.  because output can be buffered, the line indicating browserid startup is complete may come in a multiline chunk.  closes #550

rework mysql connection logic: fixes create_schema flag and properly reconnects to database.  closes #548

Fixing a problem with hub subscriptions not being unregistered on destroy which broke the tests.

issue #429

close #547