Implemented cert-only sql database create
Updated doc comments as per code review
Merge pull request #4 from christav/cert-only-db-create-303

Implemented cert-only sql database create. SDK side of implementing WindowsAzure/azure-sdk-tools-xplat#303
Merge pull request #602 from christav/dev

Implemented cert-only sql database create. SDK side of implementing WindowsAzure/azure-sdk-tools-xplat#303