Merge pull request #152 from MartyBurns/master

Implement Help Desk Item #85 -- Time of Use Tier attribute copied to IntervalReading
Issue # 141 - retailCustomerId is null for client_credentials based authorizations, Issue #149 - Validate ESPI scope strings
Merge pull request #155 from dfcoffin/master

Issue # 141 - retailCustomerId is null for client_credentials based authorizations, Issue #149 - Validate ESPI scope strings