* provider/datadog: Pulls v2 and removes v1 of library go-datadog-api.
See https://github.com/zorkian/go-datadog-api/issues/56 for context.
* Fixes bug in backoff implementation that decreased performance significantly.
* Uses pointers for field types, providing support of distinguishing
between if a value is set, or the default value for that type is
effective.
* provider/datadog: Convert provider to use v2 of go-datadog-api.
* provider/datadog: Update vendored library.
* provider/datadog: Update dashboard resource to reflect API updates.
Otto Jongerius