Update/revise documentation

[dcsiebe]

The documentation is out of date so I'm checking every file and updating/revising where I feel it's necessary.

api:

• analyses.md
• architecture.md
• authentication.md
• basicauths.md
• categories.md
• choice_challenges.md
• cors.md
• data_representation.md
• emailauth.md
• environments.md
• errors.md
• filters.md
• groups.md
• index.html
• jsonp.md
• oauth2.md
• organisations.md
• pagination.md
• parameters.md
• permissions.md
• profiles.md
• progress.md
• pronunciation_challenges.md
• recognitions.md
• recordings.md
• request_response_format.md
• roles.md
• speech_challenges.md
• ssl.md
• students.md
• tenants.md
• urls.md
• users.md

websocket:

• audio.md
• choice_recognitions.md
• index.html
• index.md
• pronunciation_analyses.md
• speech_recording.md