typos

[stharrold]

• [x] 20151030...md:
  • [x] Replace 'open sandbox' with 'public sandbox'. Replaced wording is more common.
• [x] 20151208...md:
  • [x] say "append public keys with ... cat >>"
  • [x] "Update the Debian system." include sudo apt-get update && sudo apt-get dist-upgrade
  • [x] Add link from "Update the Debian system" to helpful links
  • [x] Replace 'due to its intuitive' with 'for its intuitive'.
• [x] 20160110...md:
  • [x] Add '"Python Cookbook", Ch 10, "Modules and Packages"' for dsdemos package structure.
  • [x] By 'To download dsdemos', add "Also see dsdemos installation instructions."
  • [x] Replace "then checkout the new tag" with "then checkout the version's tag".