add billing_plans and billing_agreements for subscription api support
Merge branch 'master' into subscription_apis

Merge in master for nock dependency fix
Merge branch 'master' into subscription_apis

merge in master with subscription changes
Change plural to singular for billing, change replace to update
Add subscription api samples for all endpoints for billing plans and agreements, subject to change based on api spec
Add tests for billing plans and agreements, mock mode not enabled yet
Update README to point to subscription
Cover the case when listing does not provide parameters, for searching transactions provide start and end date
linting, and samples for creating billing agreements updated to log approval url and payment token
Added configure property.  Added configure test
Bump version and ensure proper status code gets propagated properly
Add test and mocks for subscription
callback patch for tests and reset mode to sandbox after live openid conenct tests
Remove port from payment mocks
Merge branch 'master' of github.com:trainerbill/rest-api-sdk-nodejs into trainerbill-master

get configuration info
linting
Merge branch 'trainerbill-master' into subscription_apis

provide a way in sdk to fetch configuration
Merge branch 'subscription_apis'

Add subscription api support to sdks. Resolves #3 and closes #38.