docs(client/html/default-template.html): #867 - header comments for integrators
docs(docs/api/options-ui,jmd): #867 - template option documentation
docs(client/html/default-template.html): #867 - more complete default HTML page
docs(docs/upgrading-to-4.jmd): #867 - upgrading page stub
feat(client/js/uploader.api.js): #867 - remove noise
fix(client/js/uploader.api.js): #867 - regression in getItemByFileId
docs(docs/_templates/macros): #867 - styling classes table macro
docs(docs/features/styling.jmd): #867 - start of styling page rewrite