Clarify response_type
Note that `state` is recommended in RFC
Fix repeated word
Clarify `redirect_uri` in POST /tokens
Clarify `refresh_token` requirements
Break out params based on grant_type for POST /tokens
Consistency
Remove /v1 for consistency
Clarify and reword POST /validate
Clarify POST /validate responses
Remove /v1 from all URLs

We can add them back later
NO TRAILING WHITESPACE
Consolidate errors for POST /validate
Remove POST /represents
Work on POST /clients