chartcatalog 1.9.0

chartcatalog 1.9.0

• Packages chartbox and chartcatalog use same version number
• Adds tools for the Down Syndrome
• Transfer repo locations to https://github.com/growthcharts/chartcatalog
• Adds GH actions R-CMD-check and pkgdown
• Creates gh-pages branch with online documentation
• Generalises get_breakpoints() to accommodate for donor choices 0-2, 2-4 and 4-18.
• Adds the get_reference_call() function to extract the proper call to clopus
• Adds D-score to yname_lookup table
• Adds a NEWS.md file to track changes to the package.