Explain SPA codes in error legend (bug 1036461)
Merge pull request #514 from kumar303/spa-error-codes

Explain SPA codes in error legend (bug 1036461)
Set buyer on transaction for Boku (bug #1034305)

- Update solitude client to send buyer
- Update boku to set buyer on transaction create
- Update tests
Merge pull request #515 from JaredKerim-Mozilla/1034305

    Set buyer on transaction for Boku (bug #1034305)