handle bad drain uri, returning 422
made logplex_db a gen_server process that owns ets tables
Merge branch 'ets_table_creation' into v56
Add default port to logplex_tcpsyslog_drain:uri
Fix whitespace and consolidate logic.
Remove old drain socket ets tables.
Merge branch 'v56' of github.com:heroku/logplex into test_suite_v56

Conflicts:
	src/logplex_db.erl
Make log_history an app env var.
Replace HEROKU_DOMAIN with CLOUD_NAME.
Use logplex_app:config instead of app get_env.
Improve defaults for stats redis.