DEFAULT CHANGE: --cmode now defaults to concurrent #1266

Job	Run time
build	8m 29s
integration-test-providers	9s
integration-tests (AZURE_DNS)	7m 54s
integration-tests (CNR)	9m 58s
integration-tests (BIND)	2m 2s
integration-tests (CLOUDFLAREAPI)	9m 30s
integration-tests (DIGITALOCEAN)	5m 9s
integration-tests (HEDNS)	13m 28s
integration-tests (GANDI_V5)	6m 20s
integration-tests (GCLOUD)	4m 9s
integration-tests (HEXONET)	4m 5s
integration-tests (NAMEDOTCOM)	4m 49s
integration-tests (NS1)	4m 47s
integration-tests (ROUTE53)	4m 14s
integration-tests (SAKURACLOUD)	4m 31s
integration-tests (TRANSIP)	12m 31s
	1h 42m 5s

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