remove account_id from configuration
Change default uri to stage-api and rename the ENV variable in the example.
Merge branch 'master' of https://github.com/govdelivery/dcmv2_client

* 'master' of https://github.com/govdelivery/dcmv2_client:
  Change default uri to stage-api and rename the ENV variable in the example.

Conflicts:
	.env.example
	lib/dcmv2.rb