fix Zaqis changes to the checkin method
add new content in JSON-queries and Checkin page
bring back to Markdown style
fix erroneous *.md links and update some redirected links
Create relative links
replace outdated links
merge and correct Zaqis changes
typos and small changes
Checkin-update-link
edited the link to make them more understandable
Updated Checkin (markdown)
Created Checkin (markdown)