Fixing HTTP header name for correlation ID
Including both headers for future payment correlation ID
Update Authorization.cs

If the ContentTypeHeader already exists, an error is thrown because the dictionary already contains a key with that name. The fix above will only add the header if it doesn't already exist.
Syntax refactoring and consolidating argument validation code
Update README.md
Fixing whitespace
Added "experience_profile_id" property
Merge pull request #50 from chris03/add-experience_profile_id-to-payment

Added "experience_profile_id" property
Updating to Payments API v1.2 spec
Updating unit tests
Reorganizing unit tests
Adding unit tests for Order object
Updating sample project with order sample
Updating changelog
Adding order feature
Added payment experience support
Moving nuget packages to versionless directories
Updating unit tests and sample projects